When he refers to the order of sharps – (F – C – G – D – A – E – B) – it’s basically the order in which each note in that pattern get’s sharpened and added to it’s Major scale – it’s a bit confusing at first to think about but it makes sense eventually – the best thing is to constantly quiz yourself about it and check if you’re correct
To help with your question,
For example – Say we’re going round the Circle starting with the Key of G (The key of G has an F# ) Next is the Key of D (that has an F# and a new added C#)-
If you were to keep going round the wheel adding a new sharp each time like that, you’d eventually get to the key of F# Major which has the notes: F# G# A# B C# D# E# – That would be the ‘correct’ way of spelling that scale, but an E# note is the exact same note as an F – no difference in pitch. –
If you went along even further to the next scale along the circle of fifths (C# Major) – you’d get C# D# E# F# G# A# B# – Again that’s how you’d technically spell the scale but the B# is just a C note.
Most people would refer to C# Major as Db Major (Less confusing spellings to deal with – Db Eb F Gb Ab Bb C – 3 b’s instead of 7 sharps haha)
So basically, in the Key that you’d sharpen E, or B, technically you’d spell it as E# or B# – But it sounds all the same!
(It’s important to remember as well that a Key is built from a Scale, so the sharps or flats you’re adding to each ‘Key’ are the exact same sharps or flats that make up each Major Scale that the key is built from.)
Feel free to drop me any questions man, as I love helping with this stuff – I struggled with it all through college
