There is a easy ways to activate mods,
OPTION 1:
All you need to do is go to the workshop browser, on the left search for the mod you want, install it and thats it the server will do the rest.
NOTE 1
You might have to double check that in the gameusersettings.ini there is a line called ActiveMods= with values in it, these values are the mod numbers if some of the mods needs to be in correct order for some mods to work
NOTE 2
In die commandline make sure you select one of the 2 commandlines that start with WORKSHOP the other 2 will be removed over time.