In constant mode, the EV is charged based on the desired power entered. No optimisation of any kind is considered, just constant charging at the specified power (amperage). The month peak is not taken into account, so be aware that it can be increased.
Most cars need minimum 6A to charge the battery, but some cars have a higher minimum. If your car does not start charging at 6A, move the slider to the right and try a higher setting.