When I first started learning Meteor, it was before Meteor Guide described a desired application structure. So I used @arunoda’s Mantra figuring it would be a fast way to have a properly set-up app structure for Meteor.
While @arunoda’s Kadira and Flow Router are brilliant and continue to be widely used, his Mantra project turned out to be a dead end. It was never turned over to the community and its forum has been shut down.
So it was time for me to remove Mantra from my app. I figured it could take a month of spare time hours to learn how to get an app running in the Meteor standard folder structure, because it took about that long to get my app running in Mantra.
In fact it only took a few days! I used
meteor create appName --full to generate the recommended folder structure and easily moved my app files over and got them working. I was very impressed with Meteor.