At moment only the documentation is explaining how to set up a new Bot character. www.game3d.ch/UAIS/UAIS_Docu.rtf
It is possible just to change the skeletal mesh and the animation bp, inside the bot character bp. Same should work for the player character in the demo character from the pack. You then make childs / instances from the Bot Character bp to get more Bots in the level. In the AI marker you then can setup what child of the bot character you want use. You may have to study, how the demo character animation bp is made. Most death handling and attacking with wepons.
if i get more time, i may make a video tutorial to show this. The Bot Character bp is a instance from the player character, and there are some functions overide, so it is more a Bot character without the player inputs. All other bots in the pack, are using childs from the Bot Character bp.
At least, i recomment, that you learn how characters and character animation work in ue4 and how they communicate with other bps like the AI bps are. The characters in the pack only are a simply example, how to get bots working with UAIS. It handle death and revive and it suport 2 different weapons for the bots.
The examble bot and also the character, using the same weapon system, melee and a fireball. the fireball could be a gun in the hand, and melee is melee, could be an cube and not sword. The AI system it self handle this 2 weapon systems in the bot character. If you make a own bot, you may would like to have 2 guns, then you would need to change that in your animations and animation bp, and using one of the bot weapon system to fire the attack.
So the best way to get familiar with UAIS, learn how the demo characters work inside the UAIS pack. The BPs are commented.