Dig a few inches into the ground in the area where you wish to build your garden. Digging down too deep will allow rodents such as rats to burrow through the garden above the landscaping mesh.
Cut the landscaping mesh to the appropriate size with scissors or a utility knife, and then lay the mesh throughout the hole you've dug for the garden. Make sure there are no gaps between the pieces of landscaping mesh. If desired, you can add an additional one or two layers of landscaping mesh to make the barrier more impenetrable.
Return the earth you excavated out of the garden to the area directly on the landscaping mesh, and then plant your vegetables, herbs or flowers. The landscaping mesh will act as a barrier to prevent burrowing rats from chewing through the roots of the plants in your garden.