You do not need to have a bank account or a paypal account. You do need to setup a wallet, either a cloud wallet or one of the full node wallets, and to connect it to the plugin via a coin adapter. All of this is detailed in the documentation and website.
To earn cryptocurrencies you do the same things you do to earn other kinds of money: provide goods and services that people want or need.
Via this website I provide access to WordPress software that does specific things with cryptocurrencies, but it is up to you to figure out which ones can help you in your business. For example, if you have setup a shop using the WooCommerce extension, you can use the WooCommerce payment gateway to enable cryptocurrency payments, or if you want to pay microtransactions to encourage recurring traffic you could set up a faucet. These are all app extensions that provide functionality on top of wallets.
I would suggest that you do not start with the question “How do I earn coins?” but with the question “What goods or services can I provide that people value?”. Cryptocurrencies, just like all forms of money, are tools that can help you grow your business, they are not a business in themselves.
To answer your previous question, when fees are paid by users they are deducted from their balance. The actual coins (minus any miner fees) remain on the site’s wallet, they are not added to any of the user accounts. You always have access to the master wallet(s) for the site and the coins are always yours.