The transition can be a mystery for a lot of golfers. I like to describe it to my students in the most basic way possible: the club went back and then it went up; it has to go down before it goes forward.
Take the club to the top of your backswing, then help it down just a little bit and swing through. It’s simple: the club goes back and up; let’s make it go down before it goes forward. The “drop down” drill, it might help you drop your scores.