In FormsCentral, once you logged in, you will be at the dashboard, you should see two tabs "Create New Form" and "My Forms" tabs. Click on the "My Forms" tab and you should be able to see all your forms. Double click on any of your form, and this will open the form in edit mode.
Now, you will have to close the form (by clicking the X next to the form name or via File menu/Close) to return to the dasboard to select another form or you can select, while in edit mode, File menu/Open, a new browser window will open showing you the dashboard with the files.
Hope this helps,