The Aero program is designed to work by working through the succesive tabs from left to right. Therefore a tab may depend on values calculated from the tabs to its left. If for example you want to calculate a nozzle mass flow you need to populate Tabs 1 and 2 first.

 Some tabs are optional and therefore not displayed by default.

Aero uses the SI unit system. 
Main Tabs
File Menu
Tools Menu
View Menu
Tool Bar