Screw sizes are cross-point Phillips Head 0 and the slightly larger cross-point PH1

Each machine screw (meaning not pointy) overall length, from the top of the flat head to the last thread, is given to the nearest millimeter (mm).

All screws have a flat pan head, basically a low disc about 3mm dia.

I use a padded mat to protect the laptop cover. Anti-static is best, but even child's placemat will do

Remove the battery pack

Remove the optical drive