So the reductant can come from either side, generating cis or trans 4-t-butyl cyclohexanol.
The t-butyl group "locks" the cyclohexane into the chair with the t-butyl equatorial.
If cis, the -OH is axial and adjacent -H equatorial.
If trans, the -OH is equatorial and adjacent -H axial.
There is a difference in chemical shift for these - the axial H is upfield (lower ppm) of the equatorial H.
There are different coupling constants for axial and equatorial H's.
Axial H's have a large (12 Hz) coupling to axial neighbors, smaller couplings (5 Hz) to equatorial neighbors.
Equatorial H's have small coupling constants (5 Hz) to both axial and equatorial neighbors.
Does this help?