When you purchase the payment plugin, you will receive a zip file called os_osm_stripecheckout_unzip_first.zip. Unzip that file, you will get the file os_osm_stripecheckout.zip. Go to Membership Pro -> Payment Plugins to install it as any other payment plugin. See https://docs.joomdonation.com/membershippro/basic-setup/payment-plugins#install-new-payment-plugin for installation instructions if needed.
https://domain.com/index.php?option=com_osmembership&task=recurring_payment_confirm&payment_method=os_stripe
(Of course, need to replace https://domain.com/ with your website url)
Stripe will also asks you for the events for webhook, select two events below:
checkout.session.completed
invoice.payment_succeeded