INDEX MATCH, MATCH and ADD for a dynamic scatter gram chart

HELP, please! My boss needs the following.
Needs all of the FTEs added together by Schedule Placement and years of service.
So, the years of service and placement need to match exactly. Then the years of service per Placement and Years of service needs to be added together.
OUTCOME: To analyze what would happen if the top weighted employees retire in three years.
I thought that an index, match, match with a sum formula would work, but I don't know how to set it up. OR...is this an IF THEN STATEMENT and SUM? Hmmm...maybe I will try that next.
The sheet labeled Certified is the one I am working on right now.
I would appreciate any help on this. THANK YOU!