Here is a complete guide how to get the 18 Steam achievements in Prison Architect.

Weirdly, Prison Architect achievements are quite rare but also easy to get. I was motivated to write this guide because of the really low rate of achievement for Polaroids and game bible (in November 2015 only 0.04% of the players earned those achievements). Also, I wasn't able to find out any guide so far. I'm happy to say it's my first guide for the Steam Community and probably the first "All Achievement" for Prison Architect.

Total of achievements : 18
Time to get them all : <5 hours

Hopeful this guide will be helpful. Please don't hesitate to propose improvement(s) in the comment. And sorry for the bad English.

Before starting:
While you can complete the achievements on you own, you can get most of them thank to the steam workshop. When you loaded a prison from steam workshop, make a save-game and load it. It will unlock the achievement triggers.
Some people find that the following tricks are cheating and I don't deny that. If you don't want to cheat, I try as much as possible to propose a legit method to get the achievements. You should know however some of the achievements are almost impossible to get (e.g. Polaroids and Bible because it is random with a incredible low spawn rate) and some people reported bugs in some versions preventing the achievements to trigger.
Remember, getting achievements is just a matter of personal fun and nobody get anything from them.

You have to finish the 5 chapters of the scenario with all the optional objectives. It is quite straightforward and you can do quickly. Follow the only golden rule :
Do not complete all the mandatory objectives before the optional objectives are completed.
This is important because sometimes the optional objectives will be removed when you progress in the story line.

For these achievements, you can build your own prison or download some prison of the community. We will see the in-game requirements to unlock them. Alternatively, I propose some prison from the Steam Workshop to get them.

Really easy achievements. You don't even need to have valid cells to host those prisoners. Just hold them in a huge Holding Cell. A few dozen of guards with tasers can help to keep them calm.
Alternatively, "Evantertainment's 1000+ Prison ! ! !" prison in Steam Workshop unlock all of them immediately (link below)
http://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=430676187lhttp://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=430676187l

Less boring than the previous achievements, you'll have to complete few objectives in sandbox mode.

引用自 Feryaz：

For "Wait and hope" if you do not have the DLC(s) it requires:
- Save prison localy
- Open the .prison save file with text editor
- Search for "BEGIN Research" and set every Progress except one to 1.000000
- Save
- Load prison and do last research

http://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=549629252&searchtext=Spare+The+Rod
https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=660267056
http://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=544384145&searchtext=Don%27t+Put+Me+In+The+Dark

-Polaroid : Most of then are gathered during the campaign but the remaining ones are a pain to get. They appear randomly on the ground when a specific event happen (e.g. prisoners are cooking). I insist on the randomly, after dozen of hours trying to get one, it could never appears. You don't get any feedback when they spawn so you should check carefully every square-meters of your prison. There are 177 Polaroid.
UPDATE [January 2017]: Erika did a awesome job to list all the polaroids with their trigger, thanks and thumb up !
http://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=822888680
Moreover StarAnastasy gives you the 14 specials prisoners that "drop" their own polaroid
https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=615194375


- Bible : This one can be more easy. The most difficult part is to get the first page. Then read it and within 24 in-game hours the next page should appears somewhere on the ground. Read it and repeat. There are 78 pages, so good luck. I personally never found the first page (after 30h+).
Tip from TheCombatWombat
"iirc like 80%-90% of the pages I found were OUTside my prison walls. So what I did was as soon as I noticed this, I made all my workers put sand everywhere outside my walls. Makes the pages MUCH easier to spot! :)"



Statistically, those are one of the rarest achievements on steam with both 0.04% earning rate (November 2015). It can be explained because there is almost no chance that you'll get them without cheating. The fault to the developers who made hundred of Polaroids and game pages to collect manually with the method above. Thus, I give also a trick to get them in few minutes. Ready ?
DISCLAIMER : don't do it if you don't want. Use the legit method above instead and good luck :)

• First of all, you need to open unlocked.txt with notepad. It can be found in the game's external directory (the same that your savegames) :
  Windows
  "c:\users\#your_user_name\AppData\Local\Introversion\Prison Architect\unlocked.txt"
  (change #your_user_name by your profile name on windows)
  Mac OS :
  "\users\#your_user_name\Library\Application Support\ Prison Architect\unlocked.txt"
  Linus :
  "~/.Prison Architect/saves/" (thank 9th Wonder for the location)
  
  Inside, you have the list of all the items that you already unlocked. If you want, you can do a backup ('save as'-> unlocked2.txt).
  
  
  
• Thus you need to get the list of all possible items. This list can be found here :
  http://pastebin.com/wuFB5xmq
  
  
• Copy/Past all the items into unlocked.txt
  
• Remove the line GameBible_77 into unlocked.txt
  
• Remove the line campaign/deathrow/transfer.png into unlocked.txt
  
• Save unlocked.txt
  
• Start the game. In extra, you should have "Game Bible 77/78" and "Polaroids 176/177"
  
  Now to get the two rare achievements :

Congratulation, you got two of the most rare steam achievements !

Congratulation, you got all the Steam Achievement and you are now part of the rare people who do.

I'm sorry again for the bad English. I would be happy to improve to guide with your help so comment, like (or unlike) and don't hesitate to contact me.