Setting up Stripe will normally be completed in conjunction with the support team.
Signup for a Stripe account: https://dashboard.stripe.com/register
Setup API details here: https://dashboard.stripe.com/test/apikeys
Setup Account details (e.g. business name etc.) in https://dashboard.stripe.com/account
Setup Webhook (for IPN) here: https://dashboard.stripe.com/test/webhooks (not needed for local testing - developers will use stripe-cli, instructions in Connect panel)
In REC+, add details to Connect > Payment Processors > Stripe
Enable method in Admin > Payment Processor Manager & enable for all zones
Test cards: https://stripe.com/docs/testing