You’ve only gone and done it. You can start browsing around the site and adding your own presentations.
We’ve started you off with a 14 day trial of our Pro account, during which you have full access to all the features of the site. After your trial, you’ll drop down to a more limited free account, or you can choose to subscribe to keep your pro features. (None of your content goes away once added.)
You can add a new presentation using the ‘+’ button at the top, but why not start by customising your profile?