first, put it down and do the robot.
Then sand all the old paint untill its smooth. all around, cut the visor out, take off the old rangfinder if you plan to replace it, if not leave it be.
Cut the back vents out, Wash the helmet in mild dish washing soap -Dawn- let it air dry over night. then bondo over the logo in the back, and the non screen accurate scratches on the right -helmet facing you- side of the visor. Attach new rangfinder.
give it a once over for anything else, then primer it with automotive laquer based primer, give that a few coats then sand the primer smooth.
Then begin the slow process of block painting. Mask of an area like the dome get reference pics and enjoy!