The first thing you should do is determine the full extent of your injuries and determine if you need to seek immediate medical treatment. If you were seriously injured, then you should go immediately to the local hospital or call your doctor and get immediate care.
The next thing you should do is contact that property owner to see if they have any kind of insurance that might cover you, such as a homeowner’s insurance or commercial policy that will cover slip-and-fall accidents on their premises. You then want to make a claim with that insurance company and go through the process with them.