Opening the bonnet is a two-step process, Chris. First you need to locate the bonnet release catch which, on a 2008 Navara is located on the lower edge of the dashboard, just to the right of the steering column. It should be just under the button that controls the VDC (stability-control) program. It should be a little plastic catch that you pull towards you. When you do, you should feel the catch `give’ and see the bonnet spring up a few millimetres.
Step two is to go around to the front of the car, and run your hand along in the space between the bonnet and the grille until you find the secondary catch which has to be pushed to one side to allow the bonnet to be lifted open. Be careful, though: Don’t let the bonnet fall on to your fingers and don’t shove your hand too far under the bonnet as there are hot components like the radiator in there as well. This second, safety catch is there in case the interior release gets bumped while the car is being driven. At which point the bonnet could fly open with interesting consequences.
From memory, that model Navara also used a manual bonnet stay rather than gas struts to hold it open. So you’ll need to hold the bonnet open and manually put the stay in place to prevent the bonnet from falling on your head.