Hi Sarge, and welcome to the forum! I don’t know if you’ve had a chance to poke around in the guides section, but there’s some excellent advice there aimed at the new player.
This is a great place to start:
I’ll let other people offer you specific advice on rosters and teams, but my general advice is this:
5* heroes are really sexy, and they’re invaluable for end-game. But 4* heroes are the backbone of being successful in this game. It takes a lot less food and feeder heroes to level them up, and a lot less unfarmable ascension materials to get them to full strength.
As excited as you are about those 5*, you’ll probably do better if you set them to one side for the moment and concentrate fully on building up a strong bench of 4* heroes. It takes patience, but the rewards are pretty good for doing it.
However you ultimately choose to proceed in the game, good luck to you!