TESedit needs to go in the main folder. You are correct about the mods and MO, TESedit is a tool, not a mod. It needs to stay outside of the Data folder. MO handles all that should go inside the data folder. In one example SKSE has most of its files outside of the data folder (in the main folder ) however it has a small folder called "data" and it needs to be handled by MO, because it is a folder that goes inside the data folder. Therefore a benefit for MO to handle it. Am i making myself clear?
As for doing what I am typing don't. I am just throwing out ideas and concepts. Feedback. You should follow the tutorial (I am in the end will have the files in the places and configuration that she set forth, just the path and way it is done is different) Then give feedback on clarity, grammar, confusing sections for you, Alternate ideas like I have done, then she can review it and make some changes to her tutorial or not.