@potok
Hold is where you need to keep you foot on a pad for an extended length (see first arrow)
Jump is where you place two feet on pads at the same time (i.e up and left)
Tap is where one foot is placed on a pad (up , down, left or right on their own)
You can see the number of holds, jumps, and taps in the message at the side of the editor
There are 4 possible taps per line (up, down, left, right)
if you take two lines there is 4 in the first and 4 in the second (4 x 4 = 16)
There are 6 possible jumps
up and left
down and left
right and left
up and right
down and right
up and down
There appear to only be 4 holds (up down left and right)
16 + 6 + 4 = 26 characters that can be represented
try using http://www.blisstonia.com/software/WebDecrypto/ to automatically solve (I found I had to do some minor edits afterwards)