Answer:
Please know I'm NOT a person who has any kind of experience with animals, and I'm just speaking from what I know from online.
First you need to clean the cats ears, kind of scrub but not too hard, make sure to use soap and when you clean use a makeup pad, or a soft washcloth.
Once you're done, dry the cats ears and apply olive oil to suffocate the mites and keep them from latching on the skin. Keep doing this several times a day and also add in some apple cider vinegar.
I'm not sure about how often it should be done or anything so you should just use the internet to be safe. Search up "Easy Home Remedies for Treating Ear Mites in Cats" and you'll see the information.
If I were you I would go to the vet instead, but if you don't have the money for it then please do your best, no matter how hard your cat squirms. Good luck and also be sure to wash your hands after to keep from getting any kind of mites in your fingers. Thoroughly.