I used to do a lot of babysitting when I was a student, regular after school days, and ad-hoc weekend evenings. On the school days I would give the DC a snack, sometimes do their reading with them, and generally keep them company watching TV or whatever until the mum or dad got in. On nice days they often played in the garden, and I would sit out with them, and very occasionally we would take a walk to the supermarket, then have a drink in the cafe there if the mum asked me to pick up something for her.
On weekends it was more of a “fun” thing, so we might do simple baking, dress up, play Barbies, then a story, then bed. I always had snacks left for me, and I would have a few hours to do my own thing (TV, reading, uni work) when the children were asleep.
Cleaning/cooking was not part of my job, although I would have happily stuck some fish fingers on if the parents were held up, and always helped put toys away, washed up what we used etc. On the evenings they were largely paying just to have someone in the house once the children were in bed - and they paid me double after midnight!