Determining position of side chain hydrogen in glycine residues from coordinates of backbone atoms
Glycine has a single hydrogen atom as its side chain:



All the six bond angles with the CA atom in the middle are about 109°
(C-CA-N, C-CA-HA3, C-CA-HA2, N-CA-HA3, N-CA-HA2 and HA3-CA-HA2 using the CCD naming convention). This defines the rough direction of the hydrogen atoms.

But which of the two hydrogens is the side chain?

If it is a left-handed protein, I'd assume that it's the hydrogen pointing toward the screen, similarly to the side chain in L-alanine:



The images are taken from WikiMedia Commons:
glycine
and L-alanine.