During calibration at startup the server looks for the head. It will send instructions to move the head a specified amount based on where it thinks it is, and the camera images the bed and sends that information by wifi to the server. the server will respond with further instructions and the head will move again, and send another image to the server. That’s the reason for the pause, the communication back and forth. it’s also the reason a solid WIFI connection is required.
The dance should result in the head under the camera where the server sees the glowforge logo directly underneath the camera, and will travel to the left limit and jocky the gantry a bit and park the head in the upper left corner. That’s when the server is satisfied it knows where the head is, and considers itself synced with the machine. Calibrated.
Just let it finish its dance and you will be good to go. I took a sharpie and indexed where the gantry should be and where the head should be when it is directly under the camera. Before I turn it on, I position the head there so the server sees it and doesn’t need to search for it. Might only save a couple of seconds, but the server never has to play hide and seek.
It is normal for the button to light up when the machine is exicuting instruction.