How can I manually create metadata?

Is it possible to manually create metadata (and add a custom cover) for a movie or series for which there are no entries in the online databases?

Found the solution to this. It is actually already described on the Firecore website. Here are the links just in case anyone else is trying to do the same.

What would be nice though if there was some kind of small program which would allow creating the necessary XML files. Of course, I can use the sample XML file and edit it with notepad but a small program where this information can be entered would be more convenient.

I know there are NFO file editors, which makes creating NFO files easier. Is there something similar for these XML files?

Are nfo and xml metadata files actually the same and just the file extension is different? Or are there differences in how they are structured?