Select a filename up to a certain character

I have some music files that are formatted like this:

Artist Name - Song Name

How do I convert the artist name (up until " -") in the filename to the artist tag?
I saw some other threads like this but I'm a total dummy with regex.

Thanks in advance

There is no need for Regex.

Take the Convert -> Filename-Tag menue.
Format String:
%artist% - %dummy%
or if you will take the title-tag from the filename too:
%artist% - %title%

this worked, thank you!