How exactly does a foreclosure work??

My parents are about to lose their house. They obviously are behind on some payments as my father and I (I was helping as much as I can) were laid off and my mother alone doesn't make enough to support the household. If they don't come up with thousands of dollars the bank will foreclose on their home. So my question is...how exactly does a foreclosure work? If they don't come up with the money, the bank will take the house..do they take the home owner's belongings also? Would it be better to try and sell the house and move out before the foreclosure takes place? We are so fed up with all of this we want out of the house already and want to move on with maybe having to rent a house or a apartment/duplex or something just to get everything caught up with. Any help or advice would be really helpful, thanks!!