Hi! So I'm still a beginner and I'm in the middle of Guitar Fundamentals 2, I want to start writing my own stuff. So I got the sheet music for a song that I like listening to and I wanted to get an idea of song structure and the construction of the melody. However I'm kind of confused about something and I hope someone can help me out.

Now the song is in 4/4 time and the second bar is a G Major chord. The bar ends with 2 non-harmonic tones. The first non-harmonic tone is approached by a skip down from a B to a F. From the F it steps down to a E in the same direction. I don't know a lot of theory but I looked online and found that this is kind of close to an Appoggiatura, however an Appoggiatura skips then steps in the opposite direction to a chord tone, I believe. Just wondering if someone can explain how that works and what the name might be.

Also is E a non chord tone for the G Major chord? I know that the G major chord that was taught in Fundamentals 1 has our fingers on G, B and G and the rest are open but I read somewhere that E is apart of the scale for G major.

Sorry for the long question, I was just really confused when I came across this and my theory knowledge is not that great.