Reach RS2/RS2+ has several LEDs which are used as status indicators for different parts of the system.
The lights above the power button indicate the battery charge level. If the loading animation is over, then you can connect your phone to Reach.
During boot, Reach RS2/RS2+ enters a network scan state and searches for known networks to connect to. If it doesn't find a known network, it switches to hotspot mode.
This LED is used to display Emlid Flow RTK status. RTK status has two colors: white and blue. White indicates incoming corrections, and blue indicates whether outgoing corrections are enabled. If the outgoing ones are turned off, there will only be a white LED. If enabled, the light will switch between white and blue every two seconds.
The LED on the Power button shows two things: whether the receiver is on/off and the point collection process. When Reach is turned on, it lights up with a solid white light. When the point collection has started, the light flashes rapidly.