Only multiplayer mode is supported, so you will need 2 devices: one for thimblerigger and another one for the victim. Devices should be connected to the same Wi-Fi network segment.
If you are thimblerigger - start the game, wait for the victim, put ball and few cups then move cups.
If you are victim - connect the game, watch and guess.
App released under AGPL license, source code available at https://github.com/js-labs/ShellsMP