First of all you need to be tested. Go
here and follow the instructions.
A good idea would be to download Hamachi, get it
here. Follow the on screen instructions and you'll be set up in no time.
If you don't already have it, download KCVDS from
here. KCVDS is the most used online Duel System in LDA. Don't download the 1.19 version unless you cannot update your 1.16 version otherwise your card images will all be blank. You can update version 1.16 through your start menu.
Welcome to LDA, good luck with your test and I hope you enjoy your time here.