The page structure is quite complex, the below links will cover a lot of it, but does not include things like In-memory OLTP structures.

http://www.sqlservercentral.com/blogs/practicalsqldba/2012/08/12/sql-server-understanding-the-data-page-structure/ - "SQL Server: Understanding the Data Page Structure"

Paul Randall knows a LOT about storage as he did a LOT of work on DBCC in the 2005 timeframe:

https://www.sqlskills.com/blogs/paul/inside-the-storage-engine-anatomy-of-a-page/ - "Inside the Storage Engine: Anatomy of a page"

https://www.sqlskills.com/blogs/paul/inside-the-storage-engine-anatomy-of-a-record/ - "Inside the Storage Engine: Anatomy of a record"

Also found this recently which covers items you might not consider:

http://rusanu.com/2011/10/20/sql-server-table-columns-under-the-hood/ - "SQL Server table columns under the hood"

Regards,
David.