Once you have signed in into your Buy Me A Coffee account head over to Settings page from your Dashboard.
Click on Connect Stripe
Sign in with an existing Stripe account to connect to your Buy Me A Coffee account
Or Sign Up if you don't have an account and complete the registration form
Once you have filled in the form scroll to the bottom of the page and click the Authorise access to this account
You will be now re-directed back to your Buy Me A Coffee page, and your account will be now successfully connected to Stripe.