Does anyone know any guides to take my family around Bransk?
Brańsk is a very small town so my best bet would be to try in Bielsk Podlaski, a city located some 25km away. I would recommend you contact the PTTK, it is an organization present all around Poland and they have guides for practically every region and city. The Bielsk Podlaski branch doesn't have its own website but I found these details on the web:
Address: ul. Mickiewicza 50/54, 17-100 Bielsk Podlaski
+48 85 730 30 24
+48 508 194 630
The things is that I'm not sure if they'll have any guides who speak English. You should still try, but if it doesn't work out, try contacting the regional branch in Białystok responsible for the whole Podlaskie Voivodship. You can find the contact details here: http://www.bialystok.pttk.pl/kontakt.php
It's more likely that they can refer you to people who speak English, but keep in mind that Brańsk is not really a touristic place, so I don't know if they'll have people who both speak English and are specialized in this area of Podlasie.
I hope this helps at least a bit!
Thank you so much for all this information. I really appreciate it.