You can use a plugin called “WooCommerce” to sell your products using a payment gateway.
- Install & Activate WooCommerce
- Go through the setup wizard
- Setup the Payment Gateway in WooCommerce Settings
- Add your products one by one so that it is displayed on the Shop Page. Add the Name of the Product, the price, Short and Long description, Product Picture and Publish.
- Add the Shop Page on your Menu to view the products
- If you have many products, Install & Activate the Import any XML or CSV File to WordPress Plugin