Once you entered your Full Name and Master Password in the web version, it takes may be 10 seconds before you are shown the Site page. Then you can enter your Site information AND also select which type of password (just below site (basic, medium, pin, etc).
Oh I see. Then we can assume you have a browser issue, old browsers like IE may not work. I'm only guessing here.
It is stated at the top of the first page "BETA - This site may not yet work on your browser.".