Type FindCharacter NPCname - for example you want to add Medreth to your party, you type ' FindCharacter Medreth'. The way you do it is simple, you just need to be on the same map with the npc. (It's been reported that a creature that joined your party this way may be bugged after you reload a save in which you have it already joined your party or after you transition to another area, so exercise caution and only use this command to experiment) But like I said, you can just use the mod and not worry about anything else, achievements will still work.
Achievements will be reactivated and cheats disabled when you reload the game (it's not necessary to exit the game entirely). This will activate cheats for this game, but will disable achievements. If you're not using the IE Mod, some of these commands will not be available at all, others will not be usable by default, you need to enable cheats by typing in iroll20s. If you're using the IE Mod, you can just use these commands without any prerequisites. Console Commands (Cheats) for Pillars of Eternity
