Is this question related to the certification exam? (judging from your post title). If so, we can't really answer, but if not please share with me the activity/step in the training material that you are having troubles with and I'm happy to help you.
Einas "Give a Man a Fish, and You Feed Him for a Day. Teach a Man To Fish, and You Feed Him for a Lifetime"
In the step where I am supposed to pull the volume data from Data02 SKU Volumes to Rev02. I have tried multiple LOOKUP formulas which have not worked. I initially thought it might be a simple reference but swithced to a LOOKUP formula. The formula listed below in one of the ones that have failed.I believe the syntax is correct. I understand you cannot give an answer, just looking for guidance.
As @einas.ibrahim pointed out you have to think about when to use LOOKUP and when to use SUM. In this case the data is already in the structured hierarchy you want so you actually don't need either. Just reference the line item.
your data is in G3, P3, and Month
Your target is in G3, P2, and Month
The only difference is the P3 to P2 and since those two are in the same structured hierarchy, you won't need to use SUM. Anaplan is smart enough to add those up for you since you already defined the relationship between those to levels (P2 is the PARENT of P3 in your lists).
'DATA02 SKU Volumes'.Volumes - Try It!
If that doesn't work then you need to check your dimensions and whether or not the data in SKU Volumes actually loaded.