Unlock gated content after Stripe payment

Hi there, I would like to ask for advice.

I have:

  • created a website: https://www.cestazasvobodou.cz/
  • created a gated page “Knihovna (Library)”
  • also created “Users > Access Groups > Paid Access” and connected with “Knihovna (Library)”
  • opened an account on Stripe and created a product there for a monthly subscription
  • linked my subscription product from Stripe to button on my WebFlow page

How can I set up that when someone will purchase it, it will unlock him/her a gated content page?

I found info that I should do that thought Webhooks, but nowhere is info on how.
Thank you very much for your time!