Assuming that your volumes throughout your process are close to the predicted values, then the calculation is already done for you within the program. You need to enter the volume and gravity of the wort collected from the mash to get the comparison of mash efficiency. Likewise, if you complete the data entry of gravity and volume into the fermenter, you will get a calculated brew house or total efficiency. I have attached a screen capture of the sessions tab where these are displayed and circled the mash efficiency comparison in red; the total efficiency in blue.