Metaio Creator
The easiest way to create an AREL application is to use Metaio Creator. Creator lets you configure a scene with basic logic and export this either as a channel for junaio, or a package that can be used with the Metaio SDK directly.
Advanced users can then use the exported AREL package and extend it to their needs. Apart from exporting to an app within Creator (see these tutorials) you can also just export the plain AREL package by using Export as AREL package from the Creator Export menu.