I assume you were following the Quick-Start Tutorial on Leaflet's website? You can look at the source of the example for the full break down on how it works internally. Leaflet doesn't use any Cloudmade specific stuff other than itself, so you shouldn't have to refer to the Cloudmade tool.
If you're looking for some basic Javascript tutorials (the language that Leaflet uses), there are some mentioned on Language Books/Tutorials for Popular Languages.