A short guide on creating a GPG master key, before then creating subkeys for it.
A short post on GPG subkeys and why you should use them.
Link your Yubikey with GPG
Learn about the different key file formats.
My cheatsheet for using GnuPG.
Learn how to add GPG support to the Nautilus file browser so that you can easily encrypt and decrypt files.
Learn how to generate GPG keys.