The bass staff

You can already play these five notes. This lesson only has to show you what they look like.

The five lines are the same five lines. What changed is the clef at the front, and a clef is the thing that decides which pitch each line stands for — so the same position on the page means a different note than it did before.

That is not a second system to learn. It is one system with a different anchor, and the anchor is easier here than it was on the treble staff.