Start walking and follow the path and you'll reach a small pond. Tamp a fish onto your spear and move on a short distance.
You'll reach a broad terrain full of dinosaurs (small ones). Throw the spear with the fish into the terrain (thanks to that, you'll see where it lands) and take out a gun and shoot them all, when the dinosaurs run around it (before you throw the spear, don't pick up the ammo that lies there, because you'll lose the fish and there are only two in the pond). If you need to, repeat this.
Once it's safe, go on further. You have two paths, left and right.
By going left (by creeping), you'll reach a place with a small elevation. Go onto the elevation and tamp onto the spear a flying bug, so that later on you can throw it to distract some foes.
By going right, you'll reach a place where water with fish will be surrounded by rock from three sides. Tamp a fish onto the spear and go to the other side of the field. Use the bait to repeat the trick you did a few moments ago.
Once the terrain is clear, move on and walk between the mountain rock.
You'll meet Ann there; she will be standing on a large branch (root?). Run after her on the narrow path near the wall because she'll need your help.
She'll be attacked by dinosaurs, and you'll have to help her. Shoot every one that gets close with short rounds from machine gun (you can zoom in to aim better). Once all are dead, move on. Right after a small, twisty tunnel in the rock there will be...
...another fight. This time our clever Ann will climb onto a rock and the hungry land reptiles will attack you by jumping over the ravine. It will be a mass attack, so you better be ready for a tough fight. Shoot everything that moves, since besides the land creatures, air reptiles will come also (defend Ann from them). If you are out of ammo, a crate is nearby. You can also retreat to the tunnel for a moment, but not long because Ann won't survive...
Once all land and most air reptiles are eliminated, Ann will move on - and you follow. A little later on, another swarm of flying creatures will arrive with their 'mother', which will kidnap Ann just like Carl earlier.
But this time you aren't the one, who will save her. The Kong will.