Hello Robert,
Here is our theme step by step documentation https://luzuk.com/demo/niwas-resort-hotel/documentation/ . You may follow it.
You have to add any plugin for contact form and add shortcode in Appointment section. For that follow below steps
Go to Dashboard >> Appearance >> Customize >> Home section >> Appointment Section >> Add form shortcode.
In our theme we are using Contact Form 7 plugins.
Thank You.