Do not worry i was digging trough all that stuff for 2 weeks before i could understand what is going on.
To get that data over, make vector array in blueprint that needs it. Then get reference to that BP and fill up array there.
I am not sure how you want use that pick_rand_loc task.
Easiest way to make this is to place that random loc blueprint inside level bp, then you go trough markers locations and build local array in level BP.
For it use event “begin play”, so its done only once.
Then make vector variable inside mycharacter (or whatever bp uses that rand location thingy).
Pick random vector from array, and set that variable inside myCharacter or other BP.
ps. I wrote how to pass data over in another topic here (with pics):