About this 3D model

mickey mouse have fun printing in multicolor, it might have some problems, maybe someone better can fix the file, I'm new to multicolor printingThank you inserting the magnetic sheet from the black side becomes a beautiful magnet https://www.amazon.it/MAGNET-Expert-Ltd-Rettangoli-autoadesivi/dp/B004RFEH6C/ref=sr_1_10?crid=30KXOCLWPWRBJ&keywords=fogli+calamita&qid=1704223241&sprefix=calamita+a+fog%2Caps%2C173&sr=8-10