Please refer to this KB Article for general information on setting up your Reservation Form.
You now have the option to not use a Wizard (with Next and Previous pages) for your CMS Connected Reservation forms.
By default, your form is set to use the wizard.
You can set this option on the Settings tab under General Options.
If you are not using the Wizard please be sure to adjust the iframe height accordingly on your website (in the Embed Code) so that you don't have to scroll down to see the bottom of the form.