Bootcamp Windows Install Help

So I’m installing Windows on my MacBook Air using Bootcamp.

Everything is fine, I got to the stage where the windows installer starts, however I had to turn my MacBook off when it got there as it was so late, thinking I’d be able to just install windows next time.

The problem is I can’t find how to get back to that point? It was right on the menu of installing windows, Bootcamp now only gives the option to remove windows, surely I don’t have to start over? TIA