How to set the time on my car's digital clock/radio?

I’m the new owner of a 1991 Chrysler New Yorker. Great looking car, so far a great running car but it needed a new radio. My mechanic was able to find another Chrysler radio from nearly the same year model. The radio works great but for the life of me, I cannot figure out how to reset the time. Any suggestions?

its been a while, and even then i took the radio out and replaced it with a pioneer, but from memory,

with the car key in the on position, with the radio off, but the clock on, press and hold (like for 3 seconds one button at a time. while holding it, use the tune knob. it turns both ways one way does the hours, the other way does the minutes.

i cant remember which button does the initial activating, but there are only 7 or so buttons in it, so you will find it quickly.

also, didnt your car come with an audio booklet which covers this? (in addition to the manual)