Taking into consideraration of everything that was previously posted, this would be a group training session.
I don't know if you are restricted to teaching all employees in a set "class environment". If not, maybe this suggestion might help. One that I have used to help fellow employees.
Since the relationship of fellow employees is established, they don't mind me "standing behind them" and watching what they are doing in Excel. They think they have, or are doing, something that makes their job productive. Task was done all on their own with the knowledge that they possessed. Got the Job done.
Example: Employee uses 4 Workbooks to enter data throughout the month. Then copies certain columns/rows from each Workbook to a Summary Sheet (different workbook) for finale Report.
I restructured what was being done to just one Workbook with a few Macros and shaved off time wasted copying and pasteing.
Employee caught one right away because it was structured to what he/she was doing on a daily basis. Needless to say, there were a few steps in there that he asked me if he could use in another project he wanted to make.
The interest in "Learning" was sparked.
********* If trying to teach a newbie, I would say start by individual instrucions on something that they can grasp on. Then you will find out who actually wants to learn the intermediate or advanced tasks.
As stated, working with a group, only some will grasp, the others will like the idea of having time away from the "desk".