"There are chairs on the left and right side of the table."
So in this sentence, why isn't "いすは" accepted, whereas ”いすが” is? The other directional questions go like "いすはそのしたです", which makes this rather confusing.
The sentence says "The" table; hard to pick up, but I believe this indicates the table as the topic of the sentence. I think a better translation is "On the left and right side of the table there are chairs"
That's certainly structured more like the Japanese sentence, but I wouldn't call it a better translation, 'cause it sounds pretty unnatural.
I feel like Duolingo teaches you nothing about the structures of sentences in Japanese. If you don't change this I'm gonna stop using Duolingo.
If you didn't know this already; in school I learned the abbreviation T.T.P.O.V. Topic (は) Time (に) Place (に) Object (を) Verb. Of course, things get a bit more complex with particles like が, however, most sentences follow thins basic structure.