So far you have learned how to move in normal mode. In order to edit text, you will need to enter insert mode.
Most Vim users map their Caps Lock key to Escape. This is because it is much easier to reach the Caps Lock key than the Escape key.
If you are using Mac OS, you can map Caps Lock to Escape by going to System Preferences > Keyboard > Modifier Keys and selecting Escape from the dropdown for Caps Lock.
If you are using Windows, you can use software such as Uncap to map Caps Lock to Escape.