I let all my trial lessons have a go at an approach.
Just show them the attitude or 'picture' on the approach, tell them to image a gun sight cross hairs on the windscreen to keep the runway in the right position, then i just adjust speed with power.
Whats more important for the approach is not travelling a couple of miles downwind past the end of the runway before turning base, as some instructor do in the mistaken belief that a longer approach gives the student more time to practise the approach.