To read an RSS feed, you need an RSS Feed reader. Different kinds of softwares can be used as RSS Feed readers. There are some dedicated softwares (QuiteRSS, FeedDemon, FeedReader, RSSOwl, Shrook...), some browsers support RSS Feed reading (Firefox, recent versions of Safari), and some mail softwares also do (Thunderbird, Outlook, old versions de Mail).
Personally, I find that using the mail software is the most convenient solution. Every morning, when I open my mail, I receive, in a dedicated mailbox, ads of the seminars that have been newly announced.
To receive information from an RSS Feed, you just have to subscribe to this feed. The precise procedure to subscribe varies slightly, depending on your reader, but the overall idea is to provide the address of the feed to the reader. These addresses are the ones you can find on the RSS Feed page of this site. If you are using Thunderbird, a detailed procedure is described in the Thunderbird page. Otherwise, the Other page suggests a few other options to receive informations from this site.