Translation:The bus is in a station in Uist.
You certainly could translate it that way, but it isn't how you would say it In Gàidhlig- I think personally it helps me to translate as literally as possible, because it reminds me how to phrase in Gàidhlig. If I translate it as "at", I might later write a sentence in Gàidhlig using at instead of in, which would make no sense, but if I translate it as "in" I am more likely to use "in" in the future? Not harshing your vibe tho, you do you
Masculine nouns don't lenite with the definite article (in the nominative case) - the notes for Food 2 explains the different forms of the definite article for masculine nouns. Some feminine nouns do lenite with the definite article, depending on which letter they begin with - the notes for Animals explains the different forms of the definite article for feminine nouns. Bus is masculine, so it doesn't lenite with the definite article - am bus (if it were feminine, it would be a' bhus - am bhus is not an option).