Open a file
To open a text file in nano, change to the directory where the file is stored, type nano and pass the filename as an argument, ex.
The entire terminal screen will be taken over by the nano interface. You can start typing immediately and see your text appear in the main part of the window.
Write as normal
Everything will work as expected, including the Return key for a new line, and the Arrow keys to scroll when the file gets large enough.
At the bottom are commonly used keyboard shortcuts. The ^ indicates that you need to press Ctrl at the same time as the letter. Note that WriteOut means save.
Some shortcuts will result in a status message and a question being asked of you. Read the message, and respond according to the options presented below.
Be sure to investigate the Ctrl+G option, which will provide a help screen with all the options available.