To answer your question ...
see forum FAQs
(for creating actions):
/t/967/1
and for your particular problem:
/t/967/1
modify the settings of the example that you select the field
title
and add as format string:
%title% - %artist%
... but I wouldn't do it.
It is a much better idea to leave the artist as it is and fill the Albumartist tag instead as this used by iTunes and WMP (and others) to group albums together.
Also: if you join artist and title into the title tag then it is fairly difficult to separate them again... So please think twice.
To add a certain string to a field you use the same type of action e.g.
Title
Format String
%title% (Live)
You have to select the files that should be handled by an action and then execute the action.