The first part you will always need to do is start a session: thankfully SFM automatically pulls up a popup to create/open one.
Everything in this window is very easy to understand

Once you have a session started right click on the 'primary viewport' and click load map. This is the most important step possible!

DO NOT CLICK ANY X'S!
This is a very common mistake new users make when starting SFM for the first time so dont worry, an easy solution has been found right here: https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=1441432181
(this is an easy step):Press the + button in the top right (for this tutorial I will be using the TF2 engineer player model)

Click the icon with a rectangle and two triangles coming out of it, this is the motion editor, now press CTRL you will see diamonds/rhombuses, these are joints, click a joint, you will see a square with arrows (depending on the model's bone structure) and the bone will be highlighted (if its stretched out then switch to the rotate tool (right of the move tool) tools
What I mean by a stretched bone

Remember the motion editor? we're gonna switch to its brother, the graph editor! (posing is an important skill here!) the graph editor is kinda the same as the motion editor
(if you plan on actually animating instead of making cool pictures then please add a camera the proper way; through the + button I mentioned earlier, making it through the work camera makes (what I call) a bugged camera, ill save the bugs (that I know) for the end) next press the M key this will make your first keyframe next drag this thing Image next rotate the arm, leg, or body part of your model, it will automatically create a new keyframe

and that concludes this section of basic info.

This is another important part of your character!
character flexes allow your character to use parts of its body that doesnt have bones (example: flex for the character to smile or open its jaw) many flexes combined can either make something amazing... or this...

1. Do not drag the one or zero sliders after clicking on the animation set of a model!
   Those sliders are intended for flexes on a character, they aren't for bones.
   
2. Do not slide EVERY flex on a model to full
   the result is REALLY WEIRD
   
3. Only use the "eyeupdown" or "eyeleftright" sliders IF YOU NEED TO! This only offsets the eyes from the view target
   
4. Do not click X's on your screens

A mod is a folder within the SFM files that SFM stores models, textures, scripts, and other content
usually these are mentioned when

• Porting files from a source engine game to SFM (Garry's mod, Half Life, Team Fortress 2, and many others)
  
• Applying DLC packs for SFM

To apply a DLC pack (installed through SFM or otherwise) when running SFM through steam you should see another option called "launch SDK" this is used to apply DLC packs which are separate mods containing the specified games data (example the portal 2 content pack will have portal 2 content)

the SDK can edit the search paths for a specific mod (by default this mod is the usermod) I recommend that you have all mods added to your usermod search path
to do this click "edit search paths for selected mod" and check ALL CHECK BOXES!
now when you place a model into your SFM session you can see all available models in your model list
NOTE: you can switch between mods with the selector on the top of the model selector

This is an important step if you want to make art with SFM
You already know about posing in SFM
"But how do I make it look nicer?" you might be asking?
Its called rendering!
Right click on your viewport
Click the "Render settings..."
After that a window will pop up and (if you have your camera in the place you want it)
Check the box named "Show Ambient Occlusion"
NOTE: With Ambient Occlusion on SFM gets very slow
to fix this simply turn it off but don't forget to turn it back on when you finish changing your camera angle

Lets say you want to make a texture.
The only tools you need are

• VTFEdit[nemstools.github.io]
  
• Any image editing software (Paint works, but is not recommended.)

Open the texture you wish to modify (VTF)
Click "File" in the top left corner and click export
Edit the image in what ever way you wish (just don't change the size of the texture) using your image editor (Paint, Photoshop, whatever)
Open the image with your VTFEdit and you will see a separate window open up in the middle of your screen, just click ok. Now save it to folder in the materials folder within any SFM mod
(I usually have a folder for all my Extra textures in my usermod materials folder)

Lets say you made a special texture that you want to apply to your character.
This is a simple skill and can be applied to almost any model in SFM.
There is only one part to this and thats to allow override materials
Simply right click your model and click "Add Override Materials"
Right click again on your model
go to the "Show in element viewer" and click model
NOTE: The element viewer is a very confusing place.
Now go to the folder (should be at the bottom) named "materials"
Click the plus sign on the left
add an atribute to the material you wish to change by right clicking
this new attribute needs to be a string named "$basetexture"

Now, this might get a little confusing.

SFM reads materials straight from the materials folder meaning if the directory is C:\[insert Directory here]\materials\[other bullcrap]\[material name] It wont work
we need to get rid of everything except for whats after the materials folder from this string so it looks like [other bullcrap]\[material name]

NOTE:You can also edit the VMT files, VMT files act the same way that I explained with the previous method (example:C:\[directory]\materials\[folder]\Texture.VTF)

Texture patches are simple modifications for SFM models either found on the workshop or already included in SFM

Texture patches simply fix messed up textures
SFM applies textures when you reload SFM (So dont have SFM running while looking up workshop items)
when you load SFM after downloading a texture pack just click 'Yes to all'
Now the fixed textures are applied.

In SFM you can emulate Team Fortress 2 gameplay.
To do this click the circle button on your primary viewport. A bunch of settings will appear. After modifying these settings to your desire, click record, then after you've done what you want to do, press esc, then right click or click the plus in the top left and select 'Create animation set(s) for existing elements after this select all the models you wish to edit, click ok and your done!
This isn't the only use it has though! It can also be used to edit models on the map as well.

Me: for looking up a lot if information and clumping it together in this guide
The funny thing is I know a lot about SFM and still feel like a beginner

Keep learning, Just when you think you learned everything, there is still more to learn.