Question on Stratesy Assignment based on Customer Score

In our system, we  have defined custom scoring engine and strategies. Strategies are also being assigned and we can see customer scores.

I want to know how strategies are assigned based on customer score  i.e

score- 80 strategy  assigned is 1

score 60- strategy assigned is b

How does system identifies which strategies to be assigned based on scores. In  other words where to define in system the link between customer scores and the strategies to be assigned based on that.