I tried multiple times.
Oh, the frustration! So, I sat there a bit and thought about it.
All I knew about stamping (I am not an expert, obviously) and figured out that I needed to stabilize the metal with the stamp.
And only having two hands was part of the problem.
So I used some blue tape and tried that on the bench block.
I still did not have a good solid impression.
Next up, I taped the copper and stamp together and put it in my vise.
That way, I could just hold onto the metal and hammer away.