Hey there, here is a very quick run down on what you need to run a dedicated server for Outpost Zero.

SteamCMD - Needed to get and update the server files.
Outpost Zero FAQ[docs.google.com] - Has critical info like which ports to forward as well as other guides if this one is too confusing.
Developer Discord: Discord Invite[discord.gg]

You no longer need a beta key to get the server files!

Skip to the end for the video version!

First download and install SteamCMD.
Download and install the server files with SteamCMD, log in to SteamCMD with the following:
login anonymous

Paste this line in to get the server files:
app_update 762880 validate

If download fails with an error at or near the end run it again right away, do not restart machine or delete any files just run it again: app_update 762880 validate

Once installed navigate to:
steamcmd\steamapps\common\Outpost Zero Dedicated Server\WindowsServer

In here find the RunServer.bat file, make a copy of this file and rename the copy to what ever you want, keeping in mind this will be the file you run to start the server.

Open the new .bat file and look to the last line at the very bottom it says:
start RunServer.bat

Change where it says RunServer.bat to the name of this new .bat file.
Save and close this file then make a shortcut for it on the desktop.

Navigate to:
steamcmd\steamapps\common\Outpost Zero Dedicated Server\WindowsServer\SurvivalGame\Saved\Config\WindowsServer

If location doesn't exist run server once to generate files.
Open Game.ini file and paste the following:

[ServerSettings]
ServerName=
MaxNumberPlayers=
+SteamID=

Fill out desired settings, place the steam64ID of whoever is to be admin like the following:
+SteamID=1234
+SteamID=5678
(replace 1234 and 5678 with player's steam64ID's, each needs to be on it's own line)
You're all done, run the .bat file and if you did everything correctly then the server will run!

Here is a video showing everything mentioned above with explanations and links in the video description:
Latest video:
https://youtu.be/K-KbJLU8jzo

old video (beta key method)
https://youtu.be/NEtLxVaeSGw

This is not a guide on how to set up port forwarding but here are the ports needing to be forwarded and some general info on where to go for guides on port forwarding.

All ports to be forwarded under UDP ruling.
27015 - Steam servers, won't show in server list without this one.
7777-7778 - Game client ports. Nobody will be able to connect without these ones.

As a general rule after setting up port forwarding you should give the machine a reboot, it's not always needed but if you are sure you've set it all up correctly but it isn't working then always give it a reboot!
To get specific information on how to set up port forwarding for your router check info at
https://portforward.com/
Always be careful of any sites that ask you to allow notifications and want you to download software!