Help with code for attach and landscape with BP

Hi Guys,
I was think on tie a rope on two trees, but I cant figure out a way.
I think on make two sockets on end of the rope, and attach then to the tree.
But how i can stretch the rope ?

And how I can put some BP like “TreeBP” on painting tool ?

I make a “TreeBP” and a “RopeBP”.
Make one socket on treebp called start, and 2 on rope start and end.
But I try to make attach, but i cant. Always bug, a need some tutorial or something.
Plz help.