Nice job (if you've been working through these sequentially) on learning the top 2 strings a bit more "formally", and reading music off of the top 2 strings.
It's now time to move onto the 3rd string — the G string.
Like before, here are the notes you'll learn (for now) on the G string; only the open note (the G), and the 2nd fret, which is the A.
The first note being open doesn't need any fretting,
Next, the A note on the 2nd string should be played with your 2nd finger, fretted tightly but comfortably behind the metal bar.
It's time now to blend your brain's visual recognition of the notes with the sound and feeling of the notes. Here's the link if you'd like to review the section on music notation again.