Match Solitaire solutions are a written as a sequence of moves, optionally separated by spaces, like this:

2a *12a

Stacks are numbered left-to-right 1, 2, 3, ..., and freecells are a, b, c, ...

So, for example,

2ameans move the card on top of the second stack (2) to the first freecell (a).

Matching moves start with "*", so

*12ameans collect the match from stack 1, stack 2, and the first freecell (a).

If moves are repeated, you can optionally add ":nx" where n is the number of times to repeat the previous move, so

2a:3xmeans move a card from the second stack (2) to the first freecell (a) 3 times in a row.

That's it!