Thank you for the clarification.
Actually, in the image you are pointing to the Layout bundles & in one page you will not be able to use multiple layouts. You can kindly go through our blog link below to know about the difference in layout bundles and templates, that will be helpful for you to decide when to use which:
https://www.joomshaper.com/blog/should-you-use-a-template-or-a-layout-bundle
And, if you want to use multiple templates like you provided the links of Ensure and Travelia template, in that case you can follow the guidelines in the link below:
https://www.joomshaper.com/blog/how-to-use-two-or-more-templates-in-one-joomla-site
It will help you.