It sounds like you are using a Smart TV with built-in apps. If so, accessing your apps depends on the brand and model of your TV. In most cases, you'll need to use the remote control that came with your TV.
Some Smart TVs come with a special remote that has individual buttons for apps like Amazon and Netflix, while other Smart TV remotes may only have one "main" button that provides access to all apps. Do you have the manual that came with your TV? If not, I'm sure we can find it for you online. Please provide the brand and model number of your TV.