'데' means somewhere. 는, 은, 을 etc make an adjective. -는 is usually used with an action verb stem. 제가 사는 데는 여기예요. Here's where I live. / I live here. 제가 밥 먹는 데는 따로 있어요. There's another place where I have a meal. -은/운/ㄴ is used with an adjectival(or descriptive verb) verb stem. 여기보다 더 좋은 데로 가죠. Let's go somewhere better than here. 추운 데서 오래 있지 마세요. Don't stay long in where it's cold. (Don't stay long, it's cold outside.) 그런 데 가지 마세요. Don't go somewhere like that. 잘 데 없으면 ㅇㅇ(이)한테 물어봐요. Ask ㅇㅇ(someone's name) if you have no place to sleep. *Notice the [ㄹ] isn't used as the future tense.

You can be helped if you write examples. 예문을 써주시면 검토하는데 도움이 될 것 같아요. 새해 복많이 받으세요^0^