More and more people are getting comfortable working with Microsoft Office Online applications such as Word, Excel, PowerPoint, etc. Just the other day, my son was asking me for some help in Office Online which is what they use primarily at his high school.
Having said that, I don't see that much help out there that's specific to Office Online apps. So we at VisualSP made some!
Attached is the Excel Online quick start guide. Feel free to distribute to users if you feel that it could be useful for them as a reference guide. If you like this and want more, let me know.
FWIW... here's how we display this quick start guide to end users at their moment-of-need: