During development you should be using an nRF52840-DK, the nRF52840 Dongle is nice for testing and demo, but for development you need a proper DK with on-board programmer/debugger. So please get yourself an nRF52840-DK if you haven't already.
Searching through the Bluetooth examples for 32-bit UUID I can't really find any examples that use 32-bit by default. But it should be similiar to using 16-bit or 128-bit UUID in the advertisment packet, so I suggest to for instance take a look at any of those and change it to 32-bit.
The \peripheral_uart and \central_uart show for instance how to add a 128-bit UUID to the scan response packet during advertisment, and how to scan for it on the central side. That may be good starting points for reference. A tip: Change BT_DATA_UUID128_ALL() to BT_DATA_UUID32_ALL() in bt_data[].
During development you should be using an nRF52840-DK, the nRF52840 Dongle is nice for testing and demo, but for development you need a proper DK with on-board programmer/debugger. So please get yourself an nRF52840-DK if you haven't already.
Searching through the Bluetooth examples for 32-bit UUID I can't really find any examples that use 32-bit by default. But it should be similiar to using 16-bit or 128-bit UUID in the advertisment packet, so I suggest to for instance take a look at any of those and change it to 32-bit.
The \peripheral_uart and \central_uart show for instance how to add a 128-bit UUID to the scan response packet during advertisment, and how to scan for it on the central side. That may be good starting points for reference. A tip: Change BT_DATA_UUID128_ALL() to BT_DATA_UUID32_ALL() in bt_data[].
