What should I do if someone accused me of stealing a scooter and the police came to my house and asked me questions?

The police may issue a warrant for your arrest if they have probable cause to believe that you have or are committing a crime.  probable cause is when a police officer can articulate facts that would reasonably lead one to believe that a crime has or is being committed.  Police officers may rely on an accuser as a reliable person to make out a warrant if the person providing the facts appears to be reliable  - i.e. their story does not appear to be made up or fabricated based on their questions and interview of the accuser.  I suggest that you just sit tight and do nothing.  Do not contact the accuser in any way.  If you are arrested, make sure you hire a lawyer asap.