DIAGNOSIS This monitor does not support Power Delivery (PD) over its USB-C port. The USB-C port is for video and data only, so it won't charge your laptop.
FIX You'll need to keep your MacBook's original power adapter plugged in separately. Use the USB-C cable to connect your MacBook to the monitor's USB-C port for the display signal. Your laptop will need to draw power from its own charger.
IF THAT DIDN'T WORK If the screen isn't displaying at all over USB-C, check your MacBook's display settings. You might need to manually detect displays. Also, ensure the monitor input is set to USB-C. Press the joystick, and if needed, use the Input button to switch to the USB-C source.
HEADS UP The USB-C port on this monitor is handy for a single-cable connection to phones or tablets that support video-out, but for laptops, remember it's video-only. Don't rely on it to power your device.