The only way I know to play with bots is to check the "Fill empty slots with bots", or use the new "Practice Match vs Bots" option. Can I play a game with say only 1 bot on my team, versus only 3 bots on their team? If yes, how do I do it?
Create a practice lobby with "Fill empty slots with bots" disabled. On the lobby screen, you can click on the red arrow to the right of any player slot to add a bot player of any difficulty. By adding bots this way, you can even mix and match bots of varying difficulty levels. See the picture below for reference.