The CU7 is a customisable 3x2 key macropad with a clickable rotary encoder.
To place the keyboard into bootloader mode in order to flash it, use the reset button on the PCB.
Make and flash example for this keyboard (after setting up your build environment):
make capsunlocked/cu7:default:flash
See the build environment setup and the make instructions for more information. Brand new to QMK? Start with our Complete Newbs Guide.