I need to know how I can conduct a medical abortion at home without harming myself. I can't go to any clinics because abortion is illegal in my country.

First question is how many weeks pregnant you are and what country.
There are pills for early only.
After that - high risks of death for you through hemorrhage (bleeding) and infection.

You only do that under the supervision of a doctor. The medication given for a medical abortion is extremely strong and should not be done at home.

You don't since you will need a doctor for any of the medications, plus it is seriously dangerous, and including death