Conjugation of verb être: je suis, tu es, il/elle/on est, nous sommes, vous êtes, ils/elles sont.
Conjugation of verb suivre: je suis, tu suis, il/elle/on suit, nous suivons, vous suivez, ils/elles suivent.
So, you are right, "je suis" can mean either "I am" or "I follow". Context will tell you which is which.
I am trying to do the test outs as suggested by Duolingo. As I have reported before the female speaker's voice is incomprehensible. I have decided not to do these exercise and I do not mind loosing fluency scores .Duolingo is a learning tool not a rat race. i will only do the exercises that are reasonably comprehensible. Thank you .
Look at these structures:
a man who follows us = un homme qui nous suit: "qui" is a relative pronoun, in its subject form (subject of "suit" - "nous" is the direct object)
a man whom we follow = un homme que nous suivons: "que" is a relative pronoun, in its object form (direct object of "suivons" - the subject of the verb is "nous)