Hello! As described in the "Help Guide & Tips" document, you can add fake players directly from the UI.
In the top second row (where the current top 10 players are shown), tap/click near the left edge of the row to generate one fake player. Near the right edge of the same row, you can disable all fake players.
I highly recommend checking out the "Help Guide & Tips" document, as it explains this and many other features in detail and helps you explore all the possibilities.

