How do you get the TM block in Pokemon Black and White?

You can't get a TM block in Pokemon Black and White. There is no item in the game called a "TM block".

Perhaps you're thinking of something else? Can you provide more context or details about what you're looking for? For example:

* Are you looking for a specific TM? If so, tell me which TM you're searching for.

* Are you looking for a way to get a specific move on a Pokemon? Let me know which move and Pokemon you're interested in.

* Are you looking for a way to learn about TMs in general? I can explain how to use and find TMs in Pokemon Black and White.

I'm ready to help you find the information you need!