Hello Salini, page creation doesn’t work straight away but has some requirements in order to function
In order to be able add a page for a certain channel, that channel must have at least one URL “stem” for attaching the page, and there must be at least one prototype page available to add a new page.
Please read
https://documentation.bloomreach.com/14/library/concepts/template-composer/page-management.html and
https://documentation.bloomreach.com/14/library/concepts/hst-configuration-model/prototypepages-configuration.html
to better understand the features and their technical aspect.
However, at this stage, before you follow the prototype pages approach for end-user page creation I would highly recommend to read and potentially follow a solution based on the latest feature the experience pages
Kind regards,
Lef