How it works is very simple, SpamExperts will position itself between your mail manager and Internet when the emails are being download and depending on what it has learnt, it will discard the unwanted mail.
So that SpamExperts learns what email to eliminate and which it has to let in, it will be necessary to teach it. To do so it includes various blacklists and whitelists with which to compare folders, similitudes and differences to fine-tune its aim until it knows exactly which mails it has to leave alone.
The learning time depends on the amount of emails that are received daily and their characteristics, but in a few days we should already see totally automated convincing results.
All in all, if you want a good antispam filter, SpamExperts is an option that as well as having a very nice interface, will also also allow you to forget about unwanted mail.