Say, you have created a page using home template and it uses home component. So for example, the component path is "/apps/components/home" this path will be stored in jcr:content node when you create a page using HOME template.
example sling:resourceType =/apps/components/home property will be added to jcr:content.
When you request a page created using home template, Sling Resource Resolver will get the request and finds the path in repository and gets the the resourceType property. And it finds the component path and renders the html content from jsp file.
Thanks.
Vikram