I am not sure If I got this right. I read the related topic in 
http://www.usenetopia.com but I am not so clear. I want some confirmation on what I did
I set up the scheduler for tonight and early tomorrow. I set it to on and the time for tonight is 23:00-24:00
for tomorrow is 00:00-4:00
so, that will activate the scheduler
then, in the watch/auto area, I have set some of the NGs to DL headers every so often (** this is already working without the scheduler). Since I want to DL a specific post that will be posted tonight, I created a filter containing file x in the header, associated it with a newsgroup (ab.misc) and set a DL directory
I also set the watch and save to on for that NG
the common settings are all off, except for the get headers (this is what I think gets the headers every now an then as I indicated above with ** - but not sure -
I remember I attempted to do this before and didn't work. So, I might have done something wrong. 
the rest of the NG are mostly on default, except for the get headers of the common settings and couple of NG that have get headers every 800 minutes or so...
Any help will be appreciated. Thanks