ProMods

Hello, I'm really interested in having a go with the map editor and was just wondering if there was any way I could make additions to the ProMods map, what would I need to do? Is there a discord or something similar to work with others and have the work reviewed, etc?

You must first learn how to use the map editor, there are a large number of tutorials on youtube as well as in this section of the forum : viewforum.php?f=36 .
ProMods has an official discord yes, here is how to join it : viewtopic.php?t=32484 .
There is in particular the show your work section that allows you to show what your are doing and receive constructive criticism to improve it, as well as the mod making advice section, where as its name suggests, allows you to find and receive a large number of tips for making a mod.