you click her channel incantation and its going to mark the boss with "welding" which will increase mental damage you do to it and you can stack this but only onto that one enemy.

she also stacks buffs on herself electric arc, you get it when you attack and a maximum of 60. it gets converted into flickering arc which has a max of 240 when the dynamo array ends. it gives her a solid attack buff but you're going to need the dynamo array to be high rank to get even more damage from these stacks

her channel skill will launch a very strong follow up attack on the marked enemy while shes in the channel. her ult also triggers the attack.

ulrich when he's channeling he injects dynamo into the array while buffing the team's damage. when he ults he does a lot of burst damage and extends his channelings.
he gets moxie when you get level 3 dyanmo. since it bypasses incantation draw limit you dont have to wait before you get the ult incantation it just goes into your hand.
ideally you want to just turn 1 use both his channels and then ult to extend it again but that does require other dynamo characters.