So, how do you get them to 1?
If you look at the example at the top of this page you see that you must touch the number to be moved: do not drag! It always moves to the gap, if possible. The numbers it jumps over are subtracted resulting in a 1 or more.
A 6 that jumps over a 2 and a 3 becomes a 1: 6-2-3 = 1 or if you prefer: 6-(2+3) = 1 . So, a 1 can’t go anywhere and a 2 only can jump over a single 1 etc. Maybe it sounds complicated, but if you’ll try it you’ll see it’s a lot easier to understand than Sudoku.
Notice that it’s not forbidden to jump back and forth: a 5 may jump 4 times over the same 1 ending at the same site while a 4 may jump 3 times over a 1 ending a the opposite site!