Copy both sokoban.bin and levels.bin to the microSD card, load sokoban.bin and RUN it:
LOAD sokoban.bin
RUNThese are seriously tricky levels, so there are also two easy/medium files available at my repo. Just rename one of them to levels.bin before running the game. If you have an urge to create your own level from a sokoban 'compatible' textfile, compile and use the sokobanprep converter I wrote just for this purpose. Since it's a puzzle game, there's no sound.