If you have more concepts about square meters, square yards or square feet, the following equation may help you.
1 acre = 4047 square meters
1 acre = 4840 square yards
1 acre = 43560 square feet

If the number makes you dizzy, you can use the size of a soccer pitch to compare. The maximum size of a standard soccer pitch is 130 meters long* 90 meters wide =11,700 square meters, which is about less than 3 acres.

Hope that helps.