Check the condition of the two thermal pads under the SSD and replace them if they're damaged. If a pad remained intact on the bottom of the old SSD, carefully transfer it to its spot on the board.

If you're changing the type of SSD (single-sided or double-sided), you'll need to change the pads so they're the proper thickness.

Make sure your new pad is the correct thickness and size. Pad thickness depends on the type of your replacement SSD—2.25 mm for a single-sided SSD and 0.8 mm for a double-sided SSD.

Use a spudger or your fingers to carefully remove all of the old pad from the motherboard.

Use highly-concentrated (more than 90%) isopropyl alcohol and a lint-free cloth (or coffee filters) to clean up any thermal pad residue.

Carefully put the new pad onto the board, making sure it goes into the rectangle marked PAD AREA.