You want to change the tagfields ARTIST and TITLE and use the filename as source?
Use Covert -> Filename - Tag
Format string: %artist% - %title% - %dummy%
You can see the immediate preview id your format string matches the filename-structure.
This format string takes " - " as unique delimiter between artist and title in the filename. " - %dummy%" means that after the 3rd " - " the content is dropped.
If you want to create a permanent action, you have to define an action group:
Name: anything you think appropriate
Type: Guess values
Guessing pattern: %artist% - %title% - %dummy%