Siberian Wilderness - Using Stealth to Kill the First Two Trinity Soldiers

When you regain control after the cutscenes, Lara is perched on a branch watching and listening to a Trinity solder talking on his radio. Wait for the Melee Icon to appear above his head and then press Y/F...

...to leap down on him.

At the second prompt, press Y/F again to finish him off with a rock. Note that you receive bonus XP for stealth maneuvers and finishers.

Quickly move into the bushes ahead so a second soldier near the campfire doesn't spot you.

Wait for the him to approach. When you see the Melee Icon above his head, press Y/F to perform a stealth takedown...

...smacking him and then choking him out with your bow.

Loot both bodies for random supplies (salvage, cloth, ammunition, etc.).

This also initiates the Grab and Go Challenge. To beat it, you'll need to kill 3 enemies and loot their bodies. After these first two, you'll only need one more. Take the arrows leaning here if you need them.

Also collect some poison mushrooms from the hollow log on the northeast side of the camp.