2008 1800 headlight

As in adjustment is full down and you can't adjust up?
Or low beam only?

Then the high beams are probably blown out and you'll need to replace them, might as well change all 4 bulbs as it's a PIA to do and you won't want to go back and do it when the lows go out soon.
I am having a hard time finding the instruction

You know, if you give full details to begin with....