What are two types of substituent positions around a chair?
A cyclohexane ring commonly has a chair conformation. Each carbon has an axial hydrogen, and an equatorial hydrogen.
This is one instance where a molecular model would really come in useful. When the carbon ring is in a chair conformation, each carbon bears 2 substituents (in this case hydrogen) axial and equatorial to the plane of the ring.
The red hydrogens are axial, and the blue hydrogens are equatorial. Note that when the chair swaps conformation (which a model will easily demonstrate) axial and equatorial substituents interchange their orientation.
Should a cyclohexyl ring bear a bulky substituent, such as
Here is a video that fully explain the cyclohexane chair conformation and the type of bonds: axials and equatorials