Welcome to the wonderful world of fly fishing.
You'll need to get some practice in casting, and be able to figure out which fly to cast and when.
My suggestion would be to set up your fly rod, reel, line and leader, but leave off the fly. Then go practice on a lawn or the grassy area of a park. The grass won't damage the line, as asphalt would, and you won't accidentally hook someone. Just think of the rod as a spring and, when you back cast, you're loading up the spring. That energy will be released on the forward cast to propel the line, leader and fly.
On the back cast, it takes a little discipline to stop the movement at or near the vertical. Going much beyond vertical unloads the spring, and you don't have as much energy stored for the forward cast. It also takes just a little practice to know how long to wait between the back cast and the forward cast. Cast forward too soon, and you'll hear the leader crack like a whip, and the fly will be gone. Wait too long and the fly will be in the water behind you.
After a little practice on grass, go practice some more on the water. When you feel comfortable, tie on a fly and see if you can place it where you need it.
Forum members Tom & Margi practiced for the first time at an RV Forum rally (see attached). Now they're expert flyfisherpeople. We have a number of other members who are also flyfisherpeople.
Sorry, I didn't answer your question directly, but I can't emphasize enough that you'll learn a lot by just practicing in a harmless situation.