Add a Custom Payment Method to the Configuration Settings

I am looking to create a Custom Payment Method. There are several tutorials online, and they all say that the system.xml and config.xml are the important files. The command I used to install is:
php bin/magento setup:upgrade && php bin/magento setup:di:compile && php bin/magento setup:static-content:deploy -f

I have used multiple versions of them, however none of them have shown up under the Stores>Configuration>Sales>Payment Methods menu. What are the exact steps and magento 2 compile commands to install the custom payment method and get it installed so it is selectable?