Please Refer below Link

https://www.youtube.com/watch?v=tCAUm3MWYzk

Hello, these are some useful link I collect from forum, to give you more idea about Report in Odoo 8.

https://www.odoo.com/documentation/8.0/reference/qweb.html

https://www.odoo.com/documentation/8.0/reference/reports.html

http://blog.emiprotechnologies.com/create-qweb-report-odoo/

https://github.com/dvdhinesh/qweb/blob/master/qweb_python/README.txt

https://github.com/odoo/odoodays-2014/blob/master/v8_reporting_engine/index.rst

Refer https://doc.odoo.com/trunk/web/qweb/, it will give a good idea about Developing custom Qweb Reports