Which inspections / oil changes when necessary?

Hi together, my mother has been with the Seat Mii for a year. Should be built in 2019 or 2020, the documents have just not been there. I have neglected a bit of inspection and oil change. Would you like to do this now via a free workshop. Should I continue to follow the specifications of the manufacturer? Where can I find them? Would you like me if you could give me a tip. Thank you very much! David