Once you have logged into your wordpress website, go to the page or pages that you wish to add a link/button to your personalised online booking tool.
Click on the edit page option from the dropdown list.
Once the page is open you should see a Edit HTML option from the dropdown context menu.
Navigate to where you wish to add the button, and copy in the code that you find on the 'Online Tool' page
Once you have copied in the code it should look something like this
To view a preview of the page click on the Preview button in the main menu
You should then see a new Book Now button on your website.
If you already have a button of your own that you prefer the look of or that sits with your websites theme you can just use the point the button at the URL (which is also on the settings page)