What are the rules in KS, where do I begin when the tenant breaks the lease

Landlord and Tenent Act Kansas - Statute KSA 58-2540, start there and read the rest of the act.

If the tenant has moved out and returned the keys before the lease was up, the first thing you have to do is inspect the property for damages. Make sure you take pictures! Next you have to try to re-rent the property. The former tenant will owe you rent from the time they moved out until the time a new tenant moves in, or until their lease term is up (whichever occurs earlier).

Also, while you are trying to re-rent the property you have to send the former tenant a written, detailed breakdown of any damages you found during the inspection and how their security deposit will be applied. Usually this has to be sent within 30 days after they've moved out. You will have to check KS law for the exact time. If you haven't re-rented the property then you are allowed to say in the letter that you are withholding the balance of the security deposit until the property is re-rented and if there is any left over after you are reimbursed for your damages then it will be returned to them.

Don't forget to take lots of pictures! If there is significant damage, hang on to all of your receipts for the repairs!

I just checked. In KS you have 30 days to return the security deposit or provide a written, detailed explanation of how it was used.

To add to Lisa's excellent response, once you have re-rented the property (or the lease expires), if the tenant owes any amounts over and above the amount of the security deposit, you can then sue the tenant for those amounts. Usually such a suit comes under Small Claims limits.

The problem with a small claims suit is collecting. Unless you know where the person banks (do you have copies of rent checks) or works (reference check), it will probably be difficult to collect.