hey I'm confused how to construct 4ths and 5ths based on c scale.

This is what I mapped out so far....

But I cant find notation for these two intervals so I have to construct them myself.

****The C scale: **C B D E F G A B C

soooo take the C and go up 5, and you get **CG** obviously a 5th....

now some of the other things I mapped out:

G is obviously the 5th of C.

now when I go to my G chord map, the 5th is a D, and if you only go up 5 steps... the 5th is a B, somethings not right.

I want to map out 4ths and 5ths for the C scale.... what am I missing?