"I generally go to bed at ten."
Translation:Ich gehe gewöhnlich um zehn ins Bett.
German word order is SVO (subject verb object) Within the object there can be many elements and the general rule is that any time expression is placed first, things relating to manner are second, and time expressions are last. For this sentence: Ich (S) gehe (v) um zehn (t) gewoehnlich (m) ins Bett (p). Specifically for this sentence, I think duolingo has the biggest problem with "zu Bett" though