Swing Lara left and right so the bag to the right catches fire. After this, swing her to the burning beams so she drops on the ground. Remove the spike by tapping X [Xbox 360] or Square [PS3], then continue. Move past the sacrificial chamber and grab the [TORCH] from the side so you can burn the debris up ahead.
Move through the crack (barely fits, eh?), then relight your torch at the fire, since it went out as you moved through the waterfall. Jump on the platform to your left and set fire to the beams to clear the way. Move through the tunnel and a QTE takes place: Wiggle the left analog stick to the left and right. Make your way through the tunnel to reach the next section.
Light your torch around the corner and burn the sail keeping the cage in place. Climb the walkway, jump onto the cage and debris will fill the crate at the end of the walkway. Set fire to that debris at the upper end of the walkway, then press Y or Triangle to move it to the other side, clearing the way. [250 XP].
Escaping the Scavenger's Den.
Proceed down the tunnel and Lara will slide down. Jump from platform to platform and after this, wiggle the left analog stick to the left and right again to free Lara from the grapple. Move through the tunnel and leap over the gap, then perform the QTE correctly: You'll have to alternate LT/RT, so you tap the one, then the other (no need to hold them). After this, move the left analog stick left; then tap LT/RT again, then move the left analog stick right, then continue tapping LT/RT (or L2/R2 for Playstation 3). [300 XP].
Proceed until you reach a tree that serves as a bridge. Moving over is much easier than it looks (except in real life, of course). Keep moving until you reach an airplane. This is essentially a climbing tutorial. Ledges are usually painted white to indicate they can be climbed. As you leap towards the plane, press X [Xbox 360] or Square [Playstation 3] to "get a good grip". That's how this will be referred to in this guide from now on whenever Lara's about to lose her grip or can possibly lose it.
Move up by pressing the left analog stick up and jump with A [Xbox 360] or with Cross [PS3]. Moving across the wing is done in the same fashion, and you'll need to get a good grip again after the leap towards it. [100 XP]. Scramble up the wall at the end to find a [TWO-WAY RADIO], then proceed to inevitably slide down to the next area. (Regardless of what the map may suggest, it's impossible to get a good grip in that scene, and you will not miss out on any items.)