The first thing to prepare is our heart which is actually our soul that becomes aware of the remarkable profound pure BEAUTY of YHWH, his only begotten Son Yeshua ha Mashiach, and the Ruach that is the Holy Spirit. Then by entering into the light as it says in John 3 our evil deeds can be exposed and only then can we be born again. Then daily when we err and when we work at crosspurposes to the Will of God, ask forgiveness. Nothing is more important.
We are saved by grace alone. Jesus says in Matthew 25 in the Parable of the Sheep and the Goats that the way we treat the "least of these" is the way we treat Jesus. If we fail, then we face eternal damnation for not being righteous.
Note that Matthew 25 begins with foolish virgins not preparing and wise virgins preparing. Did you know that producing light from oil is one of the most difficult things to do? To do so in any significant way requires fat from annual butchering of livestock and rendering to make usable candles. Otherwise annual harvesting of oil bearing plants like sesame or soybeans. A usable oil can be made from birchbark extraction by making charcoal. Dried cattails can be dipped into tallow to make a torch. Pray about that.
Trimming the wick was essential so the least amount of oil was used to produce the best light. That lesson is not just a metaphor as both had zeal but both were exhausted as the wait for Jesus (bridegroom) was so long.
Water is the next prep. Without water in a collapse people will start dying after three days. Under physical demand and when rationing, they die after five days. With zero demand and totally sedentary, people die at day ten.
That means at least having a shallow well point to get potable water and then building a deep well.
Many people suddenly without city water would die.