Translation from English to Chinese Mandarin?

I understand you have a clear image of what's going on in these situations, but I don't, so some additional description may be needed. Mandarin tends to be much more explicit than English in places, and in others, much less explicit. Let's look at the phrases in turn*:

1. Please push the bins in. (I'm assuming these are the plastic trays for personal items, and they are being pushed into a scanning device, if you use the preposition "in", Mandarin requires you state "into what")
1. 请将托盘往前推--please push the tray/bin forward
(alternate: 请将托盘推入检查机箱内--please push the tray/bin into the housing of the scanning device)

2. Please take off your belt and scarf
2. 请戴下腰带、围巾（并放入托盘内）--please remove [your] belt [and] scarf (and place them in the tray/bin)

3. Do you have a laptop or water inside your bags?
3. 行李内是否有笔记本电脑，瓶装水（或其他液体）？--does your luggage contain a laptop computer, bottled water (or other liquid(s))?

4. This item is over the size limit.
4. 这个包、行李箱等物品已超过大小限制--This bag or luggage item is over the size limit

5. Would you like to exit out and drink your water?
5. 您是否想要先退出，喝下您对水？--As English

6. Would you like to go check your bag in with this item? (I don't understand this English phrase. What exactly is being checked, the bag or the item? Both? How or why does one check a bag "with" another item? It seems one might check an additional item with a bag that is already being checked, but not the other way around.)
(best guess:) 6.您想去将您的包和这个物品一起托运吗？--Would you like to go and check your bag, as well as this item ?

7. Come into (the machine) or come on in
7. 请走入扫描机--please walk into the scanning device.
(alternatively) 请往前走--please walk forward
(alternatively) 请走进来--please come in (you would not say this unless the machine is a complete enclosure, and not say...a doorway or passage)

8. Please take a step out or step out (the machine)
8. 请往前走一步--(please take a step forward)
(alternatively) 请走出扫描机--please walk out of the scanning device (be warned, saying this may cause the person to *back out* of the device)

9. Do you want me to throw is away for you?
9. 不需要的话，我可以帮您把这个扔掉。--If you have no need of this, I can throw it away for you.

10. Anything sharp, dangerous, or fragile in the bag?
10. 您的包里是否有什么锋利，危险或易碎的物品？--Are there any sharp, dangerous, or fragile items in your bag?

11. Please don't touch anything on the table till after the screening.
11. 在扫描未完成前，请不要手碰台上的任何物品。--As English

12. Please go to this lane (pointing them to that lane)
12. 请走往这个走到。--please walk to this/that lane.

13. Please go straight and make a right turn before the exit
13. 请往前走，不到在出口处那边往右转。--please walk ahead, just before the exit there, turn right.

14. Laptop and large electronics into a separate bin
15. 请将笔记本电脑和大型电子物品各分开放入托盘内。--please place laptops and large electronics into a separate bin.

*The tone of the Chinese phrases is formal/polite, as would be required in such a situation.