I imported a bunch of files via the package explorer e.g. images, stylesheets. Now I want to use them in an XPage.
How can I include them e.g. a stylesheet? If I add them via Resources what URL should I use?
There are different ways to store files in a NSF:
First you could move them in the folder structure Resources/ and then in the appropriate subfolder. In this case the files would be available in the Database perspective (If you don't want to sort them, just put them in the Resources/Files folder). Or you can just add them in the WebContent folder.
In both cases you can access them directly via xp:this.resources definition or with the url http://example.com/yourdb.nsf/style.css.
EDIT: You can add your ressources in other folders too. If you add them f.e. in a folder names src you can access them like this: http://example.com/yourdb.nsf/src/style.css. And this is the way to add them as resource:
<xp:this.resources>
<xp:styleSheet href="/src/test.css"></xp:styleSheet>
</xp:this.resources>