Ledger lines are the small horizontal lines found above and below the music staff. The purpose is to extend the staff either higher or lower. Notes are placed on these little lines (or in between) giving us an even bigger range of sound.
It’s not very difficult to learn the bass clef ledger lines. If you have been keeping up on practicing your note reading skills, this next step will be fairly simple. All we are going to do is keep using a tool you are already using and apply it to the ledger lines.