Hi I just want to know if this sentence is grammatically correct?

"Points will be assigned based on the numbers of appearances the items listed in the sub-groups appeared in the website."

I want to say that point will be assigned each time an item in the checklist appeared in the website. For example: if email are listed in website 4 times then 4 points will be assigned.

One point will be assigned for each appearance on the website of any of the items listed in the sub-groups.