For MacOS you should find the data at:
~/Libary/Application Support/bt
For Windows you should find the data at:
C:\Users\YOUR_USER\AppData\Roaming\bt
Install Nodejs
https://nodejs.org/en/download/
Install Yarn
https://classic.yarnpkg.com/en/docs/install
clone the BT github repository
load up cmd or terminal
cd into the core and desktop directories and run "yarn" for both
cd into desktop and test run the app using "yarn start"
to build the executable use "yarn dist"
if you're on windows and build fails try:
yarn build && yarn electron-builder