It's best to put the mat at one side rather than the middle, so there is a thermal gradient. You won't need a heat lamp if it's under the tank, or another mat on the wall. Most mats should provide suffiecent heat and up to 100F, so must be controlled by a thermostat. Place the thermostat and thermometer probe under the substrate to prevent the bottom from becoming to hot. Since the frog burrows, this is more important than the surface of substrate temp when using mats. A substrate of 2-3" works best with this and has to be kept moist to prevent thermal blocking of the mat. The tanks bottom should be raised for airflow aswell