Do you mean a mate reference?
You could start by reading all there is to read in the Simulation Help Topics under the entry "Contact Set" and "Connector - Bolt".
After that, I can tell you that for bolt connectors to be meaningful, you must apply a "no penetration" contact set at the interface between the two bolted parts. This ensures that the parts do not get "glued" together by the default "global contact - bonded" option.
To select the two faces in the contact set property manager is sometimes tricky, but you can use "select other" to your advantage here.
Try it out! Read the help topics, and test out what you think they mean on a small study of two plates and a couple of bolts. Then you'll know if you have the ideas correct.