MantisBT is a web based bug tracking system that was first made available to the public in November 2000. Over time it has matured and gained a lot of popularity, and now it has become one of the most popular open source bug/issue tracking systems. MantisBT is developed in PHP, with support to multiple database backends including MySQL, MS SQL, PostgreSQL and DB2. MantisBT, as a PHP script, can run on any operating system that is supported by PHP and has support for one of the DBMSes that are supported. MantisBT is known to run fine on Windows, Linux, OS/2, Mac OS X, System i and a variety of Unix operating systems.
You just need to extract all the file on your web server and follow the url
Installation Directory: mantis you need to follow the link http://yourdomain.com/mantis and just fill database username and password, default username is Administrator and password is root.
http://s21.postimg.org/tpnayz4s5/best_mantis_updated_UI.jpg
THATS IT, ENJOY