Climb up again, from that ledge, two ledges up.
Do a lateral jump, and you're done in this room.
Grab onto the moving scarab lever and onto the platform.
Go down the slide in front, and again when you reach the middle jump, and Lara will grab onto the pole.
Jump and grab the scarab, then climb up.
In the room behind the corner, there's a puma that awaits you, very eagerly. Dodge it and shoot it with the shotgun a couple of times. Grab the shotgun ammo.
In this room, above to the place where you found the ammo is a large med pack.
Climb there by using the ledges you can see in this image. It's very easy.
In the next room, two mummies await you, so be on your best fighting form!