[O] How to use the file+function capture template?

[Marcin Borkowski]

Hi all,

I'd like to configure my capture template so that I can select the
target automatically based on the thing captured (use case: I use
capture instead of Firefox bookmarks to store interesting links.  I'd
like to store links to youtube videos I'd like to watch some day under
another headline).  The manual says there is a file-function template,
but my question is: how do I use it?  I imagine that the function
should move the point to the right place in the file buffer, right?
And how to access the content (like the %:link from the bookmarklet I
use) in the elisp function?

TIA,

-- 
Marcin Borkowski
http://octd.wmi.amu.edu.pl/en/Marcin_Borkowski
Adam Mickiewicz University