This is a Palisade (or n-Cells) puzzle. The rules are:
- Thicken some of the squares' sides so the thick borders outline cells. One such cell comprises just one square; one cell comprises precisely two squares; one cell comprises three squares; and so on up to a ten-square cell.
- Any square with a number in it indicates how many of its sides are thickened. Note that if the square is along a side of the entire diagram, then that side counts as one of the thickened sides.
- Thickened sides can be used only as parts of cell outlines: no thickened side can have both of its sides in the same cell.
Note that this is among the easier Palisade puzzles. I don't recommend it if you're experienced with the genre and looking for a challenge.