How do I time a White model 2999 sewing machine?

Needle /hook timing is accomplished by adjusting the needle arm on the drive shaft at the head of the machine
There are pages on the net as to how it is done (all machines use the same principle )
However I would suggest that you have it checked at a sewing machine repair service shop
fortunately the timing seldom changes so there may be other problems that give you the impression of timing being out
missing stitches ( bobbin tension and bunching of thread under material (top thread tension) may give you the idea that the timing is out.