Vagynamite

Hello fellow humans, There are a few decent sized bodies of water on the world I've been playing on and I'm curious on how to connect them to each other. I have been trying to mess around with the World Edit but I think I'm overcomplicating things and just generally getting outsmarted. I'm basically just trying to create small little rivers so I can effectively raft around (and eventually use the sailboat, hopefully). If anybody has any tips, I would greatly appreciate it.