how does one accept responsibility for possession

What is the name of your state (only U.S. law)? ca

recently my friend and i were arrested for possession of a controlled substance. neither one of us gave statements to police. we exercised our right to remain silent. but i am going to accept responsibility and do not know how that process takes place or if there is a procedure we must follow. my friend's court date is a couple days away while mine is a few weeks away. i really can't afford a lawyer, so i need to research and make sure my pd is doing the right thing by me. any thoughts?

Never plead guilty without advice of counsel, first.

If you cannot afford an attorney, one will be appointed for you at or after arraignment.

And even if you come forward and accept responsibility for the dope that does NOT automatically mean that your friend walks away. Depending on the details, you can both be guilty of the offense.

Possession is a crime of dominion and control, not ownership.