Add-a-new-benchmark.md

@@ -12,6 +12,8 @@ All the files contained in the benchmark should follow the following convention:
 - **N**: the number of elements
 - **U**: a multiplier (M for millions, B for billions, etc.)
 
+The directory containing the files and the case name contained in the json file must also have the same base name.
+
 Example of a case **[sphere]()** containing approximately 16 millions elements: **sphere-16M**
 
 ```sh