Your visor has instructions. If the system beeps you didn't do something right.
First get into 4wd high while moving. Let off the throttle or push the clutch (manual) to make the shift easy. When the green light is steady on stop completely or go slower than 3mph. Put the tranny in neutral (auto) or completely step on the clutch (manual) then shift into low range. When the light is solid you are good to go. To shift out you need to stop and reverse what you did.
The book says less than 3mph or stopped for the shift into 4wd low but I always stop since figuring out 3mph is kind of a pain.
Shifting directly from 2wd to low range has a low success rate because the drivetrain is usually not lined up internally. Shifting into high while moving gets it all lined up so that shifting into low is pretty much guaranteed.
If you have a manual you do not have to shift out of gear. Just make sure the clutch is all the way down. Also I don't know if you have to be on the brake like my Ranger.
Always wait for solid lights. I got a little impatient while going into low range so I shifted into drive while the transfer case was still shifting into low. I got a nice grinding sound for that.