You should be able to just push it down until it clicks shut. Some people push down on the crest. I push down with my fingers on either side of the crest. If it still wont close it may be out of adjustment.
If this is the case you may have to turn the little black rubber stoppers on each side of the hood. They are in the front on the bottom side of the hood. They may not seem like they turn, but they do. I'm not sure if they need to be turned clockwise or counter clockwise.
The latch has some adjustment as well. But try the first two suggestions first to see if they help.
1998 Porsche 986
Threaded Mode
