For this class the version of excel that is used in examples in the desktop version of excel.
On a mac device you would open the finder and then to the applications folder. In the application folder look for excel then double click on the excel icon to launch it.
On a windows device click on the start icon in the bottom left hand corner of your computer screen and click on that. A menu will come up displaying the different applications installed on your device. Scroll through that list for excel then click on excel to launch excel.
If are using a Chromebook finding the formulas can instead be found by click on the insert tab in the online version of excel. Then click on the function option and a menu will show with a list of different formulas.