How to pay with Woowallet only

Hello,

I saw some similar post on the way to set up the wallet. As i don’t have any skill in code, i’d rather ask in a new topic.
https://hookr.io/filters/woocommerce_available_payment_gateways/
I recently hosted my site local and i want to set up the wallet to be the only payement methode for customer. Right now i restricted it as the only payement gateway. You see the problem, how to charge a wallet with only a wallet?…
So i’d like to enable the payement on the wallet only with Stripe and Gocardless. Is there any specific part of the code i should modify?

(Please explain it as if i was 3 years old, where to add what on the code file, what does it do, if i have to add some specific things etc.)