The trainer is how you actually learn the algorithm sheet. It covers all three systems on the sheet: L4E, TL4E, and L5E. Pick the cases you want to work on, and every scramble it deals will land in one of them. That way you’re always practicing something you chose, not whatever happens to come up. Drill mode feeds you cases with a timer. Recap mode goes through every case you’ve enabled exactly once, which is a good way to find out what has stuck. There are also modes for case recognition and for reading full solutions. If a case keeps beating you, look it up on the Algorithms sheet, or paste a scramble into the Solver and compare approaches. Progress saves in this browser on its own, and if you sign in at the top right it follows you to other devices.