
This question has been answered by multiple community members. See the first response.
Nothing. Leave that out. It will use the default sorting which is the resource tree hierarchy. (or any other parent you wish to show the children of, or alternately, if you're using it on the parent resource itself, set &parents=`[[*id]]` to use the current resource)
It doesn't say it specifically in the documentation, that I noticed but default for sortBy is the resource tree structure.
You can set &sort=`menuindex` to it then you can use &sortdir=`ASC` or &sortdir=`DESC` depending which way you want them to be sorted. Cant remember which is default but would guess DESC
