If none of them are working, then it will probably be a fuse as you probably won't have any running lights either. If not then, you need to go to a car parts store, and get a repair manual for your car. They cost about $16.00 Or, go to a Public Library.
You didn't mention the year, make and model vehicle but I would imagine you will have to remove the dash cluster to gain access to the rear of the cluster to change bulbs.
I have changed the driver's side bulb and checked all of the fuses,now the passenger side stays on hibeam only, nothing seems to work. And now the truck will not enguage into gear at all? any advice?
the bulb is probably blown there like a headlight bulb low beam hibeam so if its blown it will just be illuminated and not flash
you start by removing the chromed Ring which is held in place by 1 screw at the top center; then you remove the Inner screws which hold the black ring to the headlamp Bucket, which holds the headlamp in place; WARNING: do not confuse these screws with the headlight Aim Adjustment screws which you can identify by a white plastic spacer and Spring behind them. do not touch those. Once the black ring is loosened and removed, the headlamp will tend to fall off, so keep your hand in front of the glass lamp. Pull the glass headlamp out from the Bucket, then disconnect the Electrical Plug from the rear of the headlamp, get the new replacement, re-connect the Plg to it, then reassemble both rings in reverse. this applies to all 4 headlamps. Same procedure and warnings apply.