You need to jump to the angled block beneath the ledge you were standing before, after crawling through the opening and before jumping to grab the handholds on the rock. The yellow X shows where you need to land Lara.

Having the hut to your back, walk to the back left corner of the wooden ledge. Turn 45 degrees to the right in order to aim the angled block. Notice the overhanging rock above. You need to be careful not to bump Lara's head on it. Angle Lara so that her head is just to the left of the overhanging rock. Take a running jump WITHOUT pressing Action or you will not reach the block. Lara will pass just to the left of the overhanging rock and you need to turn her right whilst in midair.