Place the baskets on the ground where you have chosen to build the wall. If it is a pre-made basket, and the sides are already attached to the base, they them flat down with the base in the right location. If they are not attached, place the base in the right location, and sides in position around the base.
If you are using wire mesh then cut a base and a lid of the same size, two ends of the same size, and two equal sides. Put the base in position, and all the sides you just cut out, around it.
For baskets, make sure to take the galvanized wire and wrap it around the corners and sides to make the rectangle shape, and leave the lid open for now so you can fill it with the rocks of your choice. For wire mesh, follow the same steps but leave the lid open.