You need to use the grids to draw rectangles which meet the requirements to help you put the answers in on the right.
1) Short side of 7 and long side of 9.
2) Short side of 9 and long side of 10.
3) Short side of 3 and long side of 8.
4) Short side of 4 and long side of 9.
5) Short side of 3 and long side of 5.
6) Short side of 6 and long side of 8.
7) Short side of 1 and long side of 2
8) Both sides 10 (this is technically a square).
9) Short side of 6 and long side of 9.
10) Short side of 7 and long side of 8.
11) Short side of 2 and long side of 3.
12) Short side of 6 and long side of 9.
You can draw these a few different ways to still get a correct result, so above are just one way of doing it.