Hi kongondo,
a download has the template "download"
and a category currenty has the default-template (basic-page) but could be changed.
In the download-template I set a field called "download_category" where I can select a single Page (the category).
And a Category could have multiple downloads.
And yes, the output should be something like a nested <ul> list .. like the Pagetree in the Backend of PW.
My first try was this:
$kategorien = $pages->find("parent=/kundenbereich/downloads/kategorien/");
foreach ($kategorien as $kategorie) {
$downloads = $pages->find("template=download, sort=-date, sort=download_kategorie, download_kategorie=".$kategorie->name.", kundengruppe=".$user->kundengruppe);
foreach ($downloads as $download) {
...
But it doenst work well with the nested categories.