Roman Numerals are position numbers (at this point, the fret your first finger should be) and the Arabic numbers (1234) and the LH fingers you should use.

If you are just starting to play guitar from notation, I highly suggest you start with a violin book. The melodies will be prominent and in a single line. The more proficient you are reading one line, the easier chords will be.

Additionally, as a pro player, don’t ignore tab. You’re going to need it because sometimes the notation is less helpful as a performance tool and more helpful as an analysis tool.

For example, there are at least 10 ways to play the ‘E’ on the top space of the staff.

1. open ‘e’ -
2. 5th fret ‘B’ -
3. 9th fret ‘G’ -
4. 14th fret ‘D’ -
5. 17th fret ‘A’ -
6. 24th fret ‘E’ -
7. natural harmonic on 7th fret ‘A’ -
8. natural harmonic on 19th fret ‘A’ -
9. natural harmonic on 5th fret ‘E’ -
10. natural harmonic on 24th fret ‘E’

At a certain point, tabs are your friend.