is the camera a pawn or is it just a camera actor?
if its a pawn and you want to posses it then you would drag off the return pin of the spawn actor node and then plug that into a posses node. to get the posses node you will probably need to get a reference to the player controller first.
if its just a camera actor and you want the players view to switch to the new camera then you will want to use a view target blend. again i think you will need a reference to the player controller then you will need a set view target with blend node (i think thats the name i dont have the engine open atm).
in either case its pretty simple. below ill link a video on switching cameras.
