Obviously not everything about diabolo can be taught with any single webpage. It's important to search for more information and practice. Think while you practice and you will learn more and faster. Here are some sources for infomation:

Circus Rubberduck - www.kumiankka.com
Marko's own webpage - www.taikurimarko.net

Forums:
Diabolo.ca Community - www.diabolo.ca
Sirkusteltta Forum - www.sirkusteltta.net

Vendors:
Circus Rubberduck - www.kumiankka.com
Diabolomoves - www.diabolomoves.co.uk