Flashing dongle using Visual Studio Code rather than Segger Studio

The following instructions are for using Segger Embedded Studio to flash the dongle.

https://devzone.nordicsemi.com/guides/short-range-guides/b/getting-started/posts/nrf52840-dongle-programming-tutorial

Step 2: Adjust the linker configuration. Set FLASH_START=0x1000 to place the application right above the MBR. You should also set FLASH_SIZE=0xDF000 to make sure that there is room for the bootloader at the end of the flash. Set RAM_START=0x20000008, as the first 8 bytes are used by the MBR for interrupt forwarding and adjust the size accordingly by setting RAM_SIZE=0x3FFF8.

Any advice on how to do the equivalent in Visual Studio Code?  I don't see any similar CONFIG settings in the prj config file.