How to open controller update file

I we t to update the firmware in my controller from 1.08 to 1.09
After I download the file I am asked what do I want to use to open the file??? I don’t know .

Windows 10 machine , downloading update to thumbdrive


Per the FAQ where you downloaded the update:
Download here:
onefinity-1.0.9.tar.bz2 (2.2 MB)
(sometimes, computers (esp macs) like to ‘unzip’ or decompress the file, ensure you are loading the full zipped file ending in .bz2)

How To Install:
Updating via USB
You’ll do an update via USB using the following steps:
Copy the blue .bz2 file below onto a usb stick (it must be formatted as fat 32 or ntsf). Click the flyout menu (three bars on top left), general, under firmware click ‘UPLOAD’. Select the 1.0.9 file. Depending on your shipping date, the password to update will either be buildbotics or onefinity