There are different tabs:
- The main tab is for IC only. If you want to say anything OOC, you have to put it inside brackets [ ]. No need to use /say.
- The Tell tab can be used both IC or OOC, depends of the player. However, it's usually OOC. You can use it typing /tell *name of character* *message*. You can press F so you reply to the last player who sent you a tell.
- The NPC tab is for NPCs only. No need to use any command, just have the tab selected.
- The help tab is for help requesting, you don't need to use any commands unless you want to offer advice.
- The guild chat depends of the guild, it can be both IC and OOC (it will most likely be OOC). No need to use any special command, just have the tab selected.
Hope this will help you, any doubt, just ask