1. You need to make sure who owns the property. Check ksiega wieczysta. Is it the person who has died?
2. Make sure who is listed in the Last Will and testament and if you have any claim.
3. Pay off all outstanding debts - if it is you.
4. Put the property in the hands of an estate agent/realtor.
5. Seek professional advice re tax obligations.
6. Register with the Tax Office that you have been given the property in the Will, that it is inheritance.