Although the historical Buddha was the original teacher that taught the dharma, following the Buddhist path isn’t about having faith in the historical Buddha. The Buddha taught the dharma for many years and he always emphasize that the teachings should be validate through our own investigation and experience. Which is to say that the teacher can play pivotal role in accelerating our growth but ultimately, realizing our Buddha nature is up to us. The role of the teacher has been complicated in modern times with the commercialization of the role and misconduct of a few notable teachers. 

The sangha is the community of practitioners and historically referred to the monastic practitioners.  In modern times where lay practitioners have engaged in more serious practice, the local community that supports the practice has become a critical component of sustaining regular practice. Like all great endeavors, having people that share your view and can provide feedback to your practice can make an enormous difference.