Your village is safe during the daytime. Use the few hours you have to stock up on resources.
You will need building materials (mainly wood, stone, and metal) to build and repair your buildings and defense structures.
You also need food to save your survivors from starvation and ammunition to defend your village at night.
You can't produce enough resources in your village, so you have to send out your survivors to complete missions. Choose the missions and survivors wisely and always make sure that you have enough survivors for the night to keep the hordes at bay.
Build as many storage buildings as you can and protect them. You never know when resources might become rare or unavailable, so you want your storage buildings filled up as much as possible.
Managing your resources efficiently is crucial for your survival!