Only thing I would add is that for the major seventh interval, while it’s also “legitimate” to play that note in any major part of a chord progression or walking bassline, you need to be a little careful with it as it is a very powerful leading tone that you don’t usually want to leave hanging as the last note played. It strongly wants to resolve either down a step or to the tonic, depending.
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not a hope in hell of understanding that at this early stage 
can i just start my comprehension by asking…
- are guitar chords mainly just 3 notes then? and the ‘7’ just means ‘this is a 4 note chord where you play a 7th note in the scale too’?
- does diminished just mean a semitone lower? so a flat?
- does augmented mean a semitone higher? so a sharp?
- does perfect just mean neither higher or lower, simply ‘the right note’?
if these things are true why dont they just make things simple by calling them flat or sharp or nothing? 
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Haha, yes, I totally understand that this can be a bit confusing…
I don’t play guitar, but generally, the very simplest “chord” is one often referred to as a power chord consisting of just the root and the fifth.
If you want to add some spice, bring in the 3rd as well
If you want to add even more spice, bring in the 7th as well
For playing over a chord (any chord), you can either stick to chord tones only, or you can pick notes from an appropriate scale (which is where it gets more interesting, but let’s not go there just yet).
The diminished/perfect/augmented comes from when we are looking at intervals, i.e., distances between two notes. This distance is independent on whether there are sharps or flats etc involved… (but there will be…). The “currency” for distance is a semi-tone.
So, the distance from C to G is a fifth, which is, in fact, a perfect fifth, which is equivalent to 7 semi-tones.
But, note that C# to G# also is a perfect fifth.
If you look at the interval of C to Gb, it is now only 6 semi-tones, which is called a diminished fifth.
But what if you had written C to F# (which sounds exactly the same)?? Well, this would be an augmented fourth, because we are looking at the distance of C to a flavor of F (instead of looking at the distance of C to a flavor of G, as before).
Primes, fourths, fifths and octaves can be diminished, perfect, or augmented.
Second, thirds, sixths and sevenths can be minor or major (and, rarely, diminished or augmented).
So, why have two names for the same thing (C-F# is an augmented fourth, and C-Gb is a diminished fifth but sound exactly the same)?? Because musical context might require you to use either one or the other (in order to avoid confusion, believe it or not 
)
So, yeah, you are not “wrong” in your points 2) to 4), but it’s not quite the entire picture 
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thank you very much, a very comprehensive answer. i dont fully understand it altho i understand it more than i did before, and i really appreciate your reply.
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Well, it was long, but really far from comprehensive 
I am happy to read though that it gave you some pointers in the right direction
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