How can we simplify and to have any hole?

[wim (Wim Dekeyser)]

I went back to the file that you posted here:

Fillet problem with boolean

hello I try to make a filet (dial 8 mm) only on the small part but the program don’t accept it, it makes a strange think. Could you please tell me how can I do? Please find the file attached. thanks a lot NBfillet edge.3dm (180.3 KB)

In the attached you will find one way of doing this step-by-step.
fillet edge-wd.3dm (780.9 KB)