Simple budget for a tight month - any advice?

We are a household of 14 and the budget no longer works. This is my first time dealing with any of this. The rent is fixed and the car payment is high. What helped you?

Sell things you do not use. I made about $950 from a weekend of listing.

A paper list of bills by due date helped me more than an app. I could see the month at a glance.