It's simple, just visit the following link https://www.facebook.com/hacked which will further help you in fixing your hacked account.
Additionally, here are the steps to recover your hacked account.
Step 1: Click the button "Your account has been compromised".
Step 2: Do you know your full login name? if so type it.
Step 3: No worries, even if you forgot the login name, their alternative options that bring back your account. For that, you must know the phone number that is been used to access the account.
Step 4: That's it. Start searching for your profile with this filters to see your account.