This expression means "to cartwheel". It's an idiom of Italian constructed using "fare". The translation should therefore be "to cartwheel" and not "the cartwheel". The cartwheel, noun, would be "la ruota".
I had understood that the infinitive could also be used for the imperative, so I put 'Do a cartwheel', but it is insisting on 'To do a cartwheel'. Have I misunderstood this?
There is an error which we should all be reporting until the sentence is fixed and then they will probably delete this discussion.
At this point, I don't know how to get back to the question to report it. :(