Gas consumption rate (in CF or liters per minute, depending on preferences) will be used by the simulator to estimate gas usage.
Risk Level adjusts the conservatism of hte algorithm.
Change altitude settings only if you want the simulation based on other than your current altitude. The Cobalt Computer's pressure sensor will base calculations on current atmospheric pressure if Current Altitude is selected.
Selecting the Gas Mixes button will allow you to set up alternate or multiple EAN mixes for use in the simulator, selecting the Switch Alerts button will allow you to program gas switches for simulated dives.