All file in one go:
Action: Guess Values
Sourceformat: $regexp($regexp(%path%,(disc|cd) \d+\\,,1),.\\(.+\\.+\\.+)..+,$1)
Guessing Pattern: %artist%\%album%\%track%%title%
or...
If you want to use the Converter instead, you can do so by combining it with the Filter (F3) and working in two steps:
Step 1:
Filter: %path% MATCHES (disc|cd) *\d+\\
Converter: Filename - Tag
Formatstring: %artist%\%album%\%dummy%\%track%%title%
Step 2:
Filter: NOT %path% MATCHES (disc|cd) *\d+\\
Converter: Filename - Tag
Formatstring: %artist%\%album%\%track%%title%