I had one as a kid, and it came with a little booklet that showed the series of moves to move pieces around. This definitely wasn’t the fastest way to solve, but it worked.

I remember it said to solve the top layer first, then align that with the correct “center” cubes on the second/middle layer. Then you’d get the “edges” of the second/middle layer in place using the series of moves. For the bottom, there was another couple sets of moves.