If you're from US you just need to log in into your account and you'll find a bag near the closet with this dress.
If you're from another country click here to be directed to a proxy, then copy and past this link to the page, after loging in into your account: www.stardoll.com/en/video/?videoId=64. Then keep in the until it fully loads, after that you can go to your suite, where you'll find the dress.
And that's it, I hope I helped and that you did like the dress.
See you next time,