If you've just installed a Ring Video Doorbell Pro and there's a blue circle flashing on the front of the Ring Video Doorbell Pro, it means the internal power cell is charging. You will have to wait until the charging process is complete before continuing setting your doorbell up.
Once the internal power cell is fully charged the blue light will no longer flash. The device will move into Setup Mode, and the light will spin.
After the Ring Video Doorbell is set up, it can take up to an hour for it to be fully charged.