I'm a complete newbie to newsgroups so please forgive me for asking stupid questions.
I am looking for a guide how to set up download managers such as Free Download Manager or Flashget in order to download nzb files from newsgroups.
I checked out newsleechers' trial version and I started off with speeds of around 700kB/s , however it keeps crashing and I prefer to use freeware anyway.
Try alt.binz here.. http://www.altbinz.com/ it's free for version 0.25. But you have to donate to be able to access the latest builds, well worth it IMO, great support and updates every few days with new features. I usually go with free apps but a donation for this is a great deal.
You can't use a regular download manager, you need a news reader. Alternatively Grabit is free, many people like it, I personally don't. Grabit here http://www.shemes.com/
Do some reading on this forum, plenty of tips and advice.
0.25.0 is free and has all the features you need. And if you decide to donate, you can donate any amount ($1 if you really want to) to get access to the private versions.