When you log into the TT Web Site Manager for the first time, you should see a page similar to the one below.

To create a new site, enter the site's details into the form as shown below and click on the "New" button.

Your site's details should appear in the list as shown below. However if you click on the "Edit" button, you will not be granted access to it because your user login does not yet have the rights to it.

To grant those rights, click on the "User management" link, this should bring up a screen like this one. Select the site in the "Site permissions" pulldown in your user's row and click the "Update" button. Your user should now have the rights to your new site. Click on the "Site Management" link to get back to the site management page.