BlazeLayout: Unknown Template

I finished the tutorial so now I want to make a small website base on what I learned.
The first thing I wanted to add is multiple pages (router…) and I found this page :

Flow-Router is working perfectly but when I try to render a template in App_body with Blaze he tells me that App_body cannot be found even if it is imported with the js file that calls render.

What am I doing wrong ?

I’m sorry it was a simple import mistake on my part.

Can you post your code here or provide a link to it?