Yes, I explained poorly but the issue is focusing the negative on the paper when enlarging. And the "focus finder" comes from this ad. Not my advertisement but this is the device I tried to use. Now it is 105 euros. I just donīt use it properly, the correct way. I will keep on trying. There has been a previous topic but under grain focusing not focus finding. I will put now the ad and the previous topic as links.
and the topic here earlier,

back to the drawing-board...