There are a couple of ways to see the glow worms. One is a nice little boatride and for the more adventurous there is Black Water rafting.
I have done both and the rafting is way better, however, it is dependent, to a degree, on a reasonable level of fitness. Not recommended for anyone with mobility issues. I have done the rafting twice now, the last time was in 2020 at age 72 and my BF was 70. It was really a relaxing ride floating through the caves staring up at the glow worms.
We did it as part of a self drive tour prior to boarding Maasdam in Auckland.
https://www.waitomo.com/black-water-rafting/legendary-black-water-rafting-co-black-labyrinth