Yes, ultimately you'll cut the steerer to a length that has it end about 2 or 3mm below the top of the stem. (anything from 1 to 8mm is fine)

It's an easy job you can do with a fine tooth hacksaw, ie. 32t per inch. This isn't precise work because nothing depends on the end. If you're worried about a straight cut, place a hose clamp on the good side of the cut.

Finish by cleaning up the edges with a file or emery cloth.

PLEASE NOTE that I don't suggest cutting it to the final length yet. Leave it a bit longer for now, using more spacers above the stem as needed. It's not rare for people to later want a higher stem.

You can always cut it shorter later, when you're sure, but cutting it longer is very difficult.