Reference issue

I am a bit perplexed by Freecad (again). I am trying to add a sketch to an existing body and get a reference pop up. I attached the screenshot of the message and the freecad file. The freecad file is pretty messy since it has been through about 30 iterations. I am trying to add a cutout on the extrusion that is highlighted. I have run into this problem before, but have been able to work around this. This time i am stumped on what to do. I don’t see why I can’t add the sketch to add a pocket. Any help i appreciated. This is the only forum i feel i can ask dumb questions in.
flatdacbase v3.FCStd (218.3 KB)

The body your trying to work in is not the Active Body, left click on the Body in the Tree view and make it Active

Thanks, that was a dumb question. I was doing thinks out of order it seems, but I appreciate your patience and help to disloge my addled brain. After selecting the object (Dac Holder), then highlighting the side I needed the pocket on, i got the message below. Since i had just made the body active, it seems redundant. I selected it again and all was well. There are times when the Freecad UI can be cryptic and frustrating.
active body