The procedure for evicting a tenant is known as a "summary proceeding" meaning that it is generally a quick proceeding but the steps must be carefully followed in order to have them properly expelled.  You have to first serve a 30 day notice (if they are a month to month tenant; tenant's with leases are another story).  After the expiration of the 30 days you serve them with a Summons and Complaint for eviction. That is when the process starts.  I would strongly suggest that you seek legal help here.  Good luck.