Most things are open, including restaurants, pubs, bars etc. and all close before curfew starts at midnight, some will measure your temperature and take your details at the entrance, once inside you pretty much do as you wish in terms or wearing a mask etc.
Some places will (also) ask you to sanitise your hands at the entrance, this also includes some shops/office buildings etc.
Masks are indeed mandatory everywhere and level of observance depends on where in town you are, and I'll leave it at that
