Before you've subscribed, a plan-and-billing-interval picker in Club Settings → Billing lets you choose monthly or yearly, Club or Club Plus, and takes you to secure checkout to set up payment. If you're still inside your trial when you subscribe, you won't be charged early. Your first payment lines up with your original trial end date.
Once you're subscribed, all ongoing changes happen through Stripe's own secure billing portal, reachable with one click from the same Billing page. This includes switching plans, updating your card, downloading invoices and cancelling. Dugout itself never stores your card details; that's handled entirely by Stripe.