How do you put on mods the support chat room just made no sense to me

While ingame, if you're on freeplay or if you're an op in a server, try ctrl+m. That bring up the mod menu.

If your in a lobby and your an op Press Ctrl+M and select any mod you please, this will also work on singleplayer, but if you aren't an op on multiplayer you won't be able to change mod, but if your not a mod you can always ask to be an op or you can just Ask for the op of the server to change the mod and if you don't know what an op looks like it will have there username and then this symbol @ also if you don't see that but you see people typing in chat and there name is green there ops and also keep in mind if you see red or Yellow there aren't ops there either game masters, In training Gaming masters, or there another rank called Legend's i think it is.