"Chair Conformations show how cyclohexane rings are oriented in space, reflecting the angles between the carbons in the rings and the positions of the groups on each carbon in the rings. 

The conformation shows the cyclohexane rings in their true, non-planar orientations.

Gauche is the relationship between two atoms/groups whose dihedral angle is more than 0o but less than 120o.

Stereogenic centers are the locations in a molecule where the interchange of any two groups will result in a new stereoisomer. 

Achiral molecules have no asymmetric carbon atoms in their structure.

Chiral molecules have different groups attached to a carbon.

Stereocenters are labeled R (clockwise) or S (counterclockwise).

Enantiomers are the chiral molecules, which are mirror images of one another, and the molecules are non-superimposable on each other. "