Appending the same string of text to a batch of track titles

I have a two language learning programs from the same publisher. The track titles are all Unit 01, Unit 02, Unit 03, etc. regardless of the language.

I wish to append the language to the track titles so they are Unit 01 German 1, Unit 02 German 1, Unit 03 German 1, etc.

Each course is thirty tracks so I'd rather not do this ninety times (for German 1, German 2, German 3).

I'm a newbie to the app. I have no idea what most of the terminology means, I don't need to become a pro user, I just wish to do this one simple thing.

How do I append <German 1> to a batch of tracks? Can someone tell me as if I were the stupidest person in the world?
I'm using Mp3Tag on a Macbook Pro.

See the FAQs:

Please note that on a Mac the action is called "Format tag field" instead of "Format value"

It's possible via Convert → Tag - Tag where you select TITLE as field and use %title% German 1 as format string:

Basically, the format string takes the existing title (using the placeholder %title%) and appends German 1.

The small preview shows how the resulting track title will look like.