How do you use mods?

[DuoMaxwell007]

I bought mods from vendors (and got em from quests) that say their for specific guns but when I open up my menu and go to mods and click on a weapon I either get "no options available" or "salvage for scrap" (or somethin like that)

[Over00]

Un-equip that weapon from all your load outs. Also make sure the weapon your trying to mod has slots available

[Tithus]

Have a search on youtube a few helpful videos on defiance gun mods.