This may help, a major scale is set up with this formula

W W H W W W H

W = 2 frets
H = 1 fret

so in the C Maj Scale

C D E F G A B C
1 2 3 4 5 6 7 8

Since C has not sharps or flats your 1st 3rd and 5th would be c-e-g

you only count the notes in that particular key not any other ones

Hope I didnt confuse you