Translation:My siblings do not know how to upload the file.
Would the sentence "Miaj gefratoj ne scipovas alsxuti la dosieron" also work?
scii = de: wissen, en: to know about... (with your brain)
povas = de: können, en: to can, to be capable (with your hands)
scipovi = de: wissen+können, fähig sein (havi tian teorian scion, kia donas la povon fari)
There are little diffences. See http://vortaro.net/#scipovi
Why are there random commas in esperanto? Ive seen nothing similar in norwegian, french, englishn or Spanish. Maybe german?
http://vortaro.net/#komo says that: Commas are used to separate different elemental elements, enabling clearer understanding.
French and German has logical, but completely different rules. There is no rule how to use commas in Esperanto, but the Esperanto use seems similar to the German use, which separates independent sub-sentences.
Prefere: “Kiom aĝas viaj gefratoj?” No accusative, as “viaj gefratoj” is the subject. And adjective/noun always agree in number (and case).
I'm not positive about this, but i believe in English, the plural form, brothers, can be used as unisex. So can't you translate this as "My brothers don't know how to upload the file"?
I've found reference to using "brother" without regard to gender, but not in the familial sense. It is more for a figurative brother like "We are all brothers". The latest example I read was in 1963 so I imagine it's old fashioned.