in this case it should be pretty easy you say you had variables for the start and end points before well create the same variables in your lazershotbp. now im guessing your using a spawn actor node to spawn your lazershot actor. if you are then just drag off the blue return pin and search for set then the name of the variable. if all went as planned you can now set the start and end point easily from the original blueprint.
dont feel bad not knowing stuff ive been working in the engine off and on for about a year and i still dont know how some things work.