Small Bit of Toast was built to be flexible. The default setup uses the root level projects/ folder to keep everything neat, and also gives your IDE a proper Micro:bit and CODAL environment allowing you to make use of IntelliSense without any extra configuration however this isn't necessary to run it.
Your projects can live anywhere, inside an IDE workspace, on the desktop, under a custom dev folder etc., The build script only needs to know where to find three things. Your project files which are either given to it by being called directly, or as the whole directory, the location of the microbit-v2-samples build.py and the resulting MICROBIT.hex file. Everything else is automatic.
The key to this is that the build script dynamically pulls your files into the CODAL source file, runs the compiler, and then returns the final hex file to wherever you started the script and so all that needs to be changed are the directory references at the top of the script.
Most users never need to touch anything after that.
The most important variable is MAIN_DIR
MAIN_DIR="$(cd "$SCRIPT_DIR/.." && pwd)"
By default its assumed that the script sits inside projects/ and that the root directory is one level up from it, however if you move where your project files are you will need to update this to match the actual path to small-bit-of-toast (or microbit-v2-samples if using the official version)
MAIN_DIR="/path/to/small-bit-of-toast"
Additionally you can similarly update it with reference to the script file such as.
MAIN_DIR="$(cd "$SCRIPT_DIR/../../alternative/location" && pwd)"
This tells the script where it can reliably find the environment and build files.
After this you should be able to run the build script in your new location as the source folder, build.oy and MICROBIT.hex can all be found inside of the MAIN_DIR, so the build script will still be able to seamlessly transfer your files, compile them, and drop of your hex file back into your working directory, wherever that might be.