Usage is pretty simple. Threads are sorted first by date, then grouped by newsgroup. This gives a time-series presentation of the posts but collapses multiple threads together for easier navigation. Within each newgroup is a set of threads. Click/tap on the newsgroup heading to open/close it. Do the same for thread headings inside the group to see the individual messages. Clicking/tapping on the username for each message will toggle presentation of the Usenet message header.