Same in Russian. You hit your friend on the shoulder, or just point in his general direction (your hand, not just the finger) and say: "Мой друг. Том". And if he's really a friend and not just someone you don't know how to introduce on the spot, you'd tell something about him before he actually arrive, may be - days before. So, you'd add "Я вам о нём говорил", or "Я вам много/часто о нём рассказывал".
And it's very important, who you are and who are these around you at the moment. друг, кореш, братан - the word you choose tells a lot about you.
What put me off here was the lack of stress on Tom. In English we would say "This is my friend TOM". Throwing away the name Tom made it sound as if Дугтом was one word, and I couldn't think what it was. (This is my FRIEND tom) Small point probably but how important is stress here?
Stress is important here. The male voice in this exercise actually says: "Это мой друг, Том". Here he is not talking about Tom, but he is talking to Tom about someone else. I as a native speaker of Russian understand this based on the fact that the word "друг" is stressed. If the speaker were introducing his friend Tom to someone, the emphasis would be on Tom's name.
Duo's "correct" answer seems to have been changed to "This is my friend Tom".
Using "It is my friend, Tom" in English, while not a good translation here, can be used in other contexts, where "it" would refer to something else, e.g., "Who is knocking on the door?" "It is my friend, Tom."