To use a MAX32625PICO (as a programmer) to program a MAX32620FTHR, you will need to connect the MAX32625PICO and the MAX32620FTHR using a 10-pin ribbon cable that comes along in the kit. Then from the Arduino IDE, under Boards, select MAX32620FTHR. Plug the PICO into the PC (without holding down the button) and if you see a DAPLINK drive then there’s no programming needed for the PICO which is the default out of box condition.
Once you program the MAX32620FTHR using the PICO, you need to press the Reset button on the MAX32620FTHR to run the application.