We must demonstrate our faith by our actions. The beauty and truth of our faith must also be promoted and evangelized. We can utilize the internet as a medium to evangelize the truth in the form of catechisms. The Pope’s encyclicals and other Church documents can be used as references to be fully knowledgeable. With this, we can, together with the Magisterium, combat the heresies in the Church.
Heresies are like a poison that harms the flock, so to speak. To keep harmful doctrines from infiltrating our souls, we require excellent shepherds. The Pope in particular should be among these good shepherds since he must oversee and reprimand a heretical bishop who is openly promoting heresies.
Locally, it is the Bishop's responsibility to reprimand heretics to stop the poison from spreading further. If they don't repent, it is probably wise to use the healing charity of excommunication. When lay people hear heresies, they should promptly contact their local bishop. In his diocese, the bishop is revered as a spiritual father, doctor, and shepherd who defends his flock.