Just for people who got the non-makerdiary version of the nrf 52840 USB Dongle (note the "MDK" in the article's dongle name): For the non-MDK dongle, the reset

Just for people who got the non-makerdiary version of the nrf 52840 USB Dongle (note the "MDK" in the article's dongle name): For the non-MDK dongle, the reset button is a side-oriented button next to the big white button (almost looks like an LED). Took me a while.