If you see 
or another green button with a slightly different message, then you are eligible to upgrade to the new UI (user interface). If you do not see the green button, then it is likely that you have already been upgraded to the the new UI.
To Upgrade:
Click 
All your previously created pages and links will be campaigns in the new UI. The look of these pages and links will stay the way they were until you edit and save changes. At that point make sure you have reviewed all the sections of the microsite. For help on which sections to correct, view this article.
For help on learning the new UI, click here.
To understand the way to create and share campaigns, click here.
To start with the new UI after first signing up, click here.