How do you install drivers in PureOS?
You would install them via the terminal (PureOS includes Tilix) using the apt command.
You don’t, all drivers are already included in PureOS’ kernel. If some devices in your computer need additional drivers, then they are likely not supported in PureOS (see: https://tracker.pureos.net/w/pureos/hardware_requirements/).
Bluetooth is behind the curtain over there.