Just emerged from the flooded Archives and trying to get a document in top of a wooden platform.  Walkthrough says use the grapple to climb up to get it but I can’t do it.  I have tried jumping and pressing X but I just hop around throwing the grapple and it doesn’t attach.  Tried standing under the platform and pressing X, nothing.  
 

what am I missing?  Feeling a little stupid.

Hi, Donna. The grapple is more than a little wonky in this game. You have the right idea though. Stand under the left side of the platform, fairly near it but not directly under the wooden part. Then jump up and press Grapple to hook the edge. This video clip shows the sequence. If it's not working, maybe try reloading the last checkpoint or even just jumping off the cliff to kill Lara so the game reloads. Resetting the area may help. Good luck!

https://youtu.be/-x3_vVnCc2A

That’s great, thank you, I’ll give it ago.

easy when you know how!  Fingers crossed.

I did it!  Thank you so much for your help Stella.