A memory "page" is simply a continuous section of physical memory that has a fixed size. In the case of HCS08 family, only the flash resource is paged. For instance, for MC9S08QE128 the page size is 16K. The size of a flash page is 16K. Note that the size of a memory page is the same as the size of that memory resource's page window in the local map.
The division of physical memory into pages is just a conceptual division. Pages do not correspond to real physical divisions of memory. Once conceptual division is done, a number is assigned to each page.