Upon starting the Blitz app, you'll be greeted with the Game selection screen. If one of the supported games is open in the background, you'll be forwarded to your active profile instead.
Step 1: Start a Game
Simply jump directly into a game. Blitz will automatically detect the game.
Step 2: Set Your Preferences
Once you hover or lock in your champion, Blitz will pop up to quickly ask for your Build preferences and Overlay settings.
Step 3: Save and Close
After clicking "Save and Close", everything should work automatically once you go into the game itself.