Emergency manual opening/closing instructions are in the car manual.

Basically take the left side carpet out of the boot (just unclip it from the
back & bend it) and you'll see a big black plastic cover over the sunroof
motor & a round plastic grommet. Remove the grommet & under it you'll find a
bolt head. Use the spark plug socket (supplied in the car's toolkit) to
close or open the sunroof manually. It's not easy to turn, and may not work
anyway if your sunroof mechanism is mechanically broken rather than having
some electrical fault.

As I hope you've now discovered there is a fuse in the fusebox for the
sunroof, it's not unusual for it to have been removed by a previous owner to
prevent accidental operation if the mechanism is already damaged.

Parts are relatively cheap but it's a time-consuming job to fix.

Malc.