Remove the old thermal pads and clean the back plate with 90% isopropyl alcohol

Using the 2.5 mm thermal pad, place one strip, measured at 5 cm x 1 cm on the back plate as outlined in red

Using the 2.5 mm thermal pad, place one strip, measured at 3.5 cm x 1.5 cm on the back plate as outlined in green

Using the 2.5 mm thermal pad, place one strip, measured at 6.5 cm x 1.5 cm on the back plate as outlined in blue