can you post a picture of the steering wheel?
if it is the wood grain style center cap--- it twists off of the mount--(counterclockwise)
if it is the regular style like a valiant/dart it has a plastic flat piece that pries up from the center of the horn ring-
if you examine the plastic piece there is a small slot-- be very careful or you will break the plastic!! work a small section at a time!!
either way-- once the center is off-- you will see the mounting screws-- tighten them up & your good!!
Lawrence