What I have done is:
Copy the .dts file into the overlays folder for running kernel dtb-* folder.
Ex:
/opt/source/dtb-4.19-ti/src/arm/overlays/
Edit the Make file in the overlays folder to add an entry for the new .dtbo file.
Note: I believe the entries not associated with the board you have can be removed.
Ex:
BONE-UART3.dtbo
BONE-UART4.dtbo
BONE-UART5.dtbo
MCP2515-dev1.dtbo
Back out to the top level folder:
Ex:
/opt/source/dtb-4.19-ti
Run make to build the platform dtb
Ex: For the PocketBeagle
make src/arm/am335x-pocketbeagle.dtb
Run make install to build the new and other .dtbo files:
Ex:
sudo make install
If it compiles without issue, a .dtbo should be located in the overlays folder and under ‘/boot/dtbs’ for the running kernel.
I hope this helps.
Cheers,
Jon