well, if you live in apartment the door next to you we use 隔壁(ge bi; means neighbor） the 2nd doors next to you, you can say 隔壁的隔壁 (ge bi de ge bi) door down form you we usually say 楼下(lou xia; means downstairs directly from you) if more than 1 floor down from you, we usually just say FLOOR NUMBER +楼 like the 3rd(4th) floor - 3(4 and etc.)楼(lou) and for houses 3 doors down from you mean the third house next to you, we say 隔壁(ge bi)第3户人家(di san hu ren jia) 人(ren:means people live in this house)家(jia: means house/family)

one more thing the pair is similar but we do separate sentence differently. in English we say If you got cash ; then we...... in Chinese you should say If(如果) you got cash then(的话) ; we......

they are pretty similar as IF.....THEN if=如果 then=的话 如果不下雨的话，我们就去商店。 If you got cash then we can go to the mall, because i lost my credit card. of course not just this one usage, but hope this example can help you to understand this pair.

I suggest you learn Chinese as a baby, not student, cause it gonna be very hard for a foreign speaker to understand Chinese grammar. like 下, it can has many meanings, e.g. lower, next, enter, action of stop, conquer, remove something from somebody, put yourself into, draw a conclusion, measure words = times, less than. I didn't write all meanings of 下. To be honest i dont really know how to answer your question, because my Chinese teacher didnt teach me when i was a child. She did teach me 留下 记下 as phrases and they are high frequently phrases, just remember it. as 停下50辆车, you can also say 停50辆车 which we we use a lot more in spoken Chinese. sorry for poor grammar :)

if you want to tell them they are NOISY, I recommend you just tell them "你们声儿太大了" in Pinyin, "ni men tai chao le " or " ni men sheng yin tai da le"