How can I calculate the amount of filament and time required for Altair to complete a print?

You can view this in MatterControl software. Open MatterControl > Select your printer > click on "Layer View" > Click "Generate" button. The print time, filament length, filament volume, and estimated weight will be displayed.

The MatterControl window has disappeared. How do I get it back?

On a Mac: Use “command+~” to get it back.

The gliders are not the same height. Is something wrong?

This is normal. The gliders may not be the same height when zeroed (or homed) because the trim adjusts the height individually on each during calibration.