My responsibilities as new executor

My Mum died two days ago. She rents out a couple of properties. One to my sister, who hasn't rent in several months. She says that she needs multiple repairs carried out in her house. She won't provide any proof, I've offered for her to let her use her rent for repair money. She refused that. She won't follow the correct procedures for with holding rent. She has also removed the paperwork for the house, so I don't know who the mortgage lender is to tell them that Mum has died. She is claiming that she has reported me to the council for none work that needs doing. Mum died two days ago!!! She claims the council have come around to assess the property. So she is trying to claim I am refusing to carry out repairs. Yet, she won't tell me what actually needs doing. I suspect that it is BS. Does anybody know what my legal rights remotely might be? It was my Mum's house but I am executor of the estate so she is claiming it's my responsibility. I didn't ask to be a landlord. Personally I want to wrap it all up