Tagging can be done using the tag panel.

A fast way is in place editing using the multiline facility.

In the column you which to modify:

One of the library tools to easily move or copy data from one tag to another.

You can use expressions while editing starting with an equal just like Excel .
To change:
I. Allegro
II. Adagio
III. Allegro
to:
Concerto for trumpet in E Op.17 - I. Allegro
Concerto for trumpet in E Op.17 - II. Adagio
Concerto for trumpet in E Op.17 - III. Allegro
Multiselect all the files and edit the name (F2 for in-place, or use the Tag Action Window) and type:
=Concerto for trumpet in E Op.17 - [Name]
You can undo (Ctrl+Z) if it doesn't work like you wanted.