なければ なりません - (I) must....
This expression means something has to be done regardless of the will of the actor.
Important Note: This is not a negative expression.
まいにち べんきょう しなければ なりません。
I must study everyday.
Particle まで に：
まで に Indicates the point in time when an act or an action should be done by the latest. That is, the point in time indicated by まで に is the time limit and the act or action is to be done before that time.
よる １２じ まで に センター へ かえらなければ なりません。
（We) must go back to the Centre by 12 0'clock at night.
*Make sure you do not confuse まで に With the particle まで Or particle に
まで Indicates the point in time when the continuously performed act or action ends.
ひる １２じ まで にほんご を べんきょう します。
（We) study Japanese until 12 o'clock noon.
に Indicates a point in time when a momentary action takes place.
あさ ６じ に おきます。
I get up at 6 o'clock in the morning.