From the start, 1022, inquisitions were for the better of the Church. You want to fight for your faith that's good... but first lets talk about what not to do.
Throughout the course of the medieval Inquisition there were times when people of faith got it right and got it horribly wrong.
For a perfect example on what not to do follow that of Simon de Montfort which his self inquisition led to 140 Albigensians were burned to death.
A better example to follow would be that of the Tribunal which would lead to almost a trial court but instead of partial proof being excepted only full-proof was required to convict someone.
During the high middle age the Inquisition was something necessary to destroy heresy even though we look back at something bad, the church never condoned these types of behavior.
In other words the perfect way to follow your faith and drive out heresy in your life is first consult a priest, then do what you need to do to save the souls of yourself and those around you... Happy Hunting!