Displayport Monitors to Macbook Air

Hello! I am trying to help my friend connect some monitors she got to her Macbook. The monitors have display ports and dvid ports in the back. I am using a displayport to HDMI cable for the monitor, and then plugging that into an adaptor from HDMI to usb c I have tried both cables, verified that the adaptor for the Macbook has power, tried a second adapter, and made sure the source on the monitors is set to displayport. Note that the monitors both turn off after selecting displayport as the source. The macbook is also plugged in and charging; I've tried with and without it charging. I have also tried to reset the Macbook after unplugging the adapter, then plugging the adapter in once it's on the login screen. Lastly, I tried to detect the displays in the settings, but they are not showing up when I try