A/D or ←/→: move · Space, W or ↑: jump.
E: grab/drop · 1/2: select A/B · R: restart.
Touch: ◀/▶, Jump, Grab / E. Choose Place A/B, then tap a matching socket. Walk off an arrival before returning.
Replacing a ring never moves the crate. Drop with its centre over ◇. Both you and the crate need clear space at the destination.