You can read as long as you want. In any reading room, it ends at 7: 00 p.m. (but the reference books end at 5: 00).

This card is your library card for going to the ground floor on the spot. You should bring your ID card. You can't enter the reading room without a card. You have to pay a deposit of 100 (actually equivalent to giving him 100, unless you don't want this card).

You can bring things, but you don't need to bring a big bag. Just use a vest bag. If not, you will be asked to deliver the package, and it is difficult to find an empty cabinet.

As for the laws and foreign documents you mentioned, there should be some (I didn't notice this, sorry). You can ask the staff.