And later you realise you are allowed to move your pieces!
Old openings

Set up your position on an analysis board and copy the FEN string. Then Tournaments - create daily tournament - show advanced options - use custom FEN string - paste your FEN string in the box. In the menus you can choose how many total players, number of rounds, number of players in a group, number of days per move, rating range, all that stuff. Then wait for enough players to join, or invite players and when you have enough guys away you go.
I sometimes remember when we were first learning chess
before we knew any proper openings
we would try to make up our own
like this one: