For a language pair that is not in trunk or staging such that you know well the two languages involved, write a document describing the main problems that Apertium developers would encounter when developing that language pair (for that, you need to know very well how Apertium works). Note that there may be two such documents, one for A→B and the other for B→A Prepare it in your user space in the Apertium wiki.It may be uploaded to the main wiki when approved.
For further information and guidance on this task, you are encouraged to come to our IRC channel.