My custom ribbon don't showing

[AlexExcel2021]

I have created ribbon follow this documentation Customizing the 2007 Office Fluent Ribbon for Developers (Part 1 of 3)
I use XML editor from Github and and editor said me that all is correct. However when I try to open my *.XLAM addins than I don't see anything in my ribbon and new event not fired.
Maybe need something additional step? Or why I don't see anything new in my ribbon?

 

[RoryA]

idMso is for built-in tabs, not your own.