I would suggest you to install raspibian lite on another SD card. then in raspi-config you need to activate the camera. then simply in terminal type “raspistill -k” and the red-light should come up. Ofcourse you would need to connect a keyboard and a hdmi monitor. Camera picture should show on your monitor. CTRL C to close camera. Once you have ensured camera works you can swap back to SD-card with Mynaturecamera.