Translation:There were two right shoes and four left ones there.
Where does the second "there" come from? I translated it as "there were two right shoes and four left ones. (English is not my mother tongue, so not sure if that's rather a question about English?)
"Byly ... [kdo/co]" is translated as "There were ... [who/what]", and "tam" is the second "there" for the local position. If it was "There were ... here", it would be "Byly tady ...".
Why isn't "2 right shoes and 4 left ones were over there," accepted? Is it because I did not type out the numbers?
No, we do not accept this even with the numbers typed out. But someone else has to comment on the grammaticality of your answer.
This may sound a little weird, but since byly means "there were" and tam means "there" (as in direction or, in this case, location), there should be two "theres" in the translation to English.