Hi,
Thanks for contacting us.
To make your site as per demo, please refer below to the documentation for a better understanding.
Please take backup of your site if any data is available before activating our premium theme.
Here is the link: https://ovationthemes.com/docs/ot-nutrition-diet-pro/
Please refer to above documentation for customization if you have imported the data.
Please let us know if you need anything further and we would be happy to help.
Many Thanks