Many native english speakers taking this course have been demanding English translations that correspond to the most natural/usual way to convey the meaning of the Hindi sentence in uk/american English. That creates confusing mismatches between the verbatim of the two sentences, like this one, with a present tense being rendered using a past tense. I personally prefer literal translations, even if the English is somewhat "broken": "he is here since/for ten minutes", in this case. Since I want to learn Hindi, not English, that would serve my purpose much better.
से often means since. You've to notice the arrangement of words too. है often means here or is. As in he's still here. When से and है are together it would be has been here. While writing how far someone is from you you'd mention the word distance so the sentence "he is 10 minutes from here" would become "he is at a distance of 10 minutes" which you can translate literally to "वो दस मिनट के दूरी पर है।"
Also gives "He is here since ten minutes" as correct. It's not grammatical English. A lot of the English translations in this lesson are incorrect and the requirements seem to jump between literal (grammatically incorrect) answers and the English that native speakers would actually use. Another example in this lesson was that the 'correct' answer was "He is here since an hour." But 'से ' was translated as 'for' in a previous answer. There isn't any consistency here. (Leaving aside the tense issues also discussed.) I'm grateful for the free lessons and appreciate the work that has gone into them. I will have some free time in a few months and will happily give some to reviewing English grammar. Is there anywhere to sign up for this?
I don't follow, in this case it's 'वह दस मिनट से यहाँ है', which is pretty exactly your literal translation? Unless you mean why is वह in front? That's because 'he' is the subject, but that's consistent with all the examples with time (incl. हर दिन etc.) I've seen on Duolingo.