Hi Rehan,
My book includes a chapter on XML that discusses XML basics and XML processing via various Java APIs, including Android's XMLPULL V1 API (which is Android's version of StAX). Appendix C, which is part of the book but distributed separately as a 96-page PDF file, and which you can download from
http://www.apress.com/9781430264545, introduces AndroidManifest.xml and discusses what gets placed inside this XML file.
All the best.
Jeff