Nouns at the beginning of the sentence vs. the end

So I just started learning Japanese and I'm using a leaning app. I'm doing alright, but I keep messing up on the placement of nouns when asking for directions (specifically asking a question). Sometimes I'm getting the answer wrong because I use the term at the beginning of the sentence and sometimes I get it wrong because I use it at the end of a sentence. The app won't explain anything except that I'm just wrong.

Google give an explanation, but I don't understand what it's saying.

Can I get a simple explanation as to when and where to use nouns when asking questions or for directions.

For example, what is the difference between "konbini wa soko desu ka" and "soko wa konbini desu ka"?