Go online, and then select 'Fetch Group List' from the Project menu. NewsCoaster will then download the entire list of newsgroups carried on your newsserver. If you set up more than one newsserver, then it will do this for the default newsserver - to download groups for other newsservers, go to the Servers page of 'Program Settings', select the newsserver, and click 'Get Groups'. Please note that this takes time, depending on the number of newsgroups and the speed of your connection.
The file is saved in text format under the name *.gl, where * is the name of your newsserver, in the NewsCoaster folder.
To view the lists, go to the Servers page under 'Program Settings', select the newsserver (if you have more than one), and click Groups Manager (or of course you can always view the file in a text editor yourself).