Select "mash profiles from the left column and then either select a mash profile similar to what you want or create your own "new mash Profile" if you select a pre installed profile by double clicking on it you will see the mash profile editor screen. If you double click on the first mash step it will bring up the mash step editor and from there you can edit the water to grain ratio and also your step temp,time ect.
Cheers
Andrew