This activity is to provide an environment ( the spiral) which is rich for exploration and opportunities for curiosity. It provides a good environment for discovery and surprise. It can help develop skill in numerical pattern spotting.
Possible approach
Depending on the pupils' experiences and abilities you may or may not provide spirals all ready for them to explore. It would be good to remind pupils of what they already know about numbers:- addition, multiplication, primes, multiples, digital roots (https://nrich.maths.org/5524)
It is worth considering giving them the freedom to explore in any way they feel inclined.
If ideas need to be shown then try offering this to them:-
Images of the spiral can be downloaded here if needed.
Key questions
What do you notice? (Both numerically and spatially)
Is there some reason why that happens?