An Unlawful Detainer case is fast. Usually, the defendant has 5 days to file a response. You can have a trial 20 days after that. In general, the defendant cannot file a cross complaint (counter-sue).
You can begin the process of preparing your paperwork, here
If the landlord wins the case, they will get a "judgment" and the tenant has to move out. The Sheriff can enforce this judgment. This means the Sheriff can physically make the tenant leave.
You cannot evict someone yourself without going through the proper steps. It is against the law. Only the Sheriff can evict someone. That is why you may need an Unlawful Detainer. You may refer to the Evictions:Landlord page for more information.
Even if a tenant is months behind on the rent, the landlord cannot:
Make the tenant move out
Get rid of the tenant’s possessions
Lock the tenant out
Cut off the water or electricity
Remove outside windows or doors
To legally evict the tenant through the process of an Unlawful Detainer, the landlord has to:
Serve the tenant with the appropriate written notice (there are several types of notice, and the one you serve on your tenant must be appropriate to your specific case circumstances)
Wait for the time period in the notice to end
File an Unlawful Detainer action if the tenant does not do what the notice asks