No, you only need to have two points, since it automatically creates the area between those two points.

With a wooden hoe, left-click on the block where you want to claim, then with the same wooden hoe, right-click where you want your claim's border to end.

After that, you do /res create (name of the residence goes here) and you are basically done unless, of course, you don't have enough money to claim the res.

To remove a res do /res remove