For Owners Manual look here: Ford Ranger Owner Manuals - 1996 to 2011 Models
Nice looking truck, clean.
There are some mileage dependent fluid changes.
O2 sensors tend to get used up around 125K miles, just the front 2, the rear O2 sees cleaner exhaust so double that.
Shift transfer case into 4WD high once a month, don't need to drive just shift it, then shift it back to 2WD.
The electric shift motor brushes can get corroded and when you do need 4WD the motor won't turn, tap on it with a hammer, and it will usually start working again, but if you move the motor once a month it will stay cleaner