Attempting to Paint Door Trim

What happens here

The painter moves to a white exterior door frame, which appears to be a trim piece. He positions himself and attempts to apply paint to the trim using the continuous-feed brush. He pauses briefly, appearing to wait for sufficient paint flow to reach the brush or for the system to pressurize. He mentions, 'It's taking a while,' indicating a potential delay in paint delivery or a need to prime the system more thoroughly. He eventually moves away from the trim without clearly showing successful application.

Goal: Demonstrate the tool's application on exterior door trim.