I am doing it in sets so it's easier to read and learn. Trying to read all of this at once is a nightmare, I should know, I tried to teach someone all of this at once
I have been asked this by a few members about intervals, an interval is the difference between one not and the other. Now I have a method for this, you should obvious look at pitch.
However the key signature is very important with this and the starting note, so for this is what I do:
1. Check the key
2. Listen to the first note
3. Hum the first note and go up in half steps until I find the next note
The last one takes some practice to be able to do but if you can do it then you will find intervals much easier. For this, get a Piano or guitar and just learn how to hum an octave from playing a chromatic scale (chromatic being all half tones). Once you have remembered how to do all of that then you will have no trouble in finding intervals