The AlertMaxx2 has a normally closed circuitry. The finger float should be installed into the red shroud as pictured below, so that it raises with the rising water level.
The finger float should be installed in accordance with the below guidance, taken from the AlertMaxx2 Ground Water O&M.
The finger float should be wired into the terminal highlighted in blue below and the blue and brown cables should be used. If you believe you have a problem with the float and the AlertMaxx2 is constantly sounding with an F1, you can link out the terminal with some spare cable to temporarily close the circuit and the AlertMaxx2 should mute and display an F3.