There are total 171 Collectibles
Challengeobjects in Tomb Raider.
The 10 Documents "Lara´s Journal"
collect you automatically (9/10) when you use Camps during the Storyprogress. The last One in this Row get you in the Ending Scene and the Achievement No Stone Left Unturned
pops up during the Endscene.
In Survivortree you have 2 Skills which help a Lot to find Collectibles. (Orienteering and Cartography)
You can set a Marker on your Map to a uncollected Item and when you use Survival Instinct ingame, you see a blue beam of light on the Location from the marked Collectible.
If you collect an Collectible, it is automatically saved. After the Story you can use fast Travel to each fast Travel Camp to collect the missing Collectibles or Challengeobjects.
The Numbers behind the linked Timelinks are the Ingame Coordinates from each Objects. In the Youtube Description you have the Timeline too.
When you Click a Item, a new Window open and the Video starts from this Time / Item. Otherwise you can watch the Videos below the Areas and click manually to the Time.
In the first Spoiler is always the Video and in the second Spoiler is the Timeline with the Collectibles, Challenges & Coordinates.Coastal Forest
PS: The 360 Solution is mine too.