Batch to Remove 1st then Add

Currently, I remove all tags first. Then I do a Filename - Tag. Then I add a comment that is the same for mostly all my tags. How can I program these 3 operations into one command?

I would leave out the removal of all tags and update only those that are incorrect.
If you still want to do it, use an action of the type "Remove fields except" and leave the field %dummy% as the last one.
An import of data from filenames can be run in an action with an action of the type "Guess value" - the syntax is the same as in the function Convert>Filename-Tag which means it works only for files with the same pattern in the filename.
To set a certain field, e.g. COMMENT, to a certain value, use an action of the type "Format value".
Actions can be grouped in an action group.
To see more about actions, see the FAQs

Thanks but I am unsure how to use the Guess Value. What do I put in for SOURCE FORMAT and GUESSING PATTERN to equal Convert> Filename-Tag?

Have you tried to import data from the filename with Convert>Filename-Tag?
As you do not show us a typical filename, I can't tell you what to put in the format string.
The source string is %_filename% or even %_directory%\%_filename%

I see...yes, it is %_directory%%_filename%. The Convert function doesn't show this...it only shows the Format String. Thanks for the help.

if you use the convert function with a string like
%album%\%track% - %title%
you can also retrieve information from the folder structure.
See the Howtos:

Thanks for that info.