Confused about pre paid mortgage expenses?

I'm trying to understand exactly what pre paid expenses mean. For example if I pre pay a whole year of home owners insurance at closing does that mean there will be no monthly charges throughout a 12 month period for the insurance or will I be paying double??!?!

Likewise, if I pay 3 months of HOA fees does that mean the following 3 months I won't pay any?

Is there a point where I catch up?
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These pre-paids are to get your account all set up. The goal here is to first pay up front for these expenses, and then you will be paying an addtional amount each month that will be added into what is called your 'escrow' account. This 'escrow' account (you will receive statements) contains the funds that will be used to pay these expenses when they next come due (taxes, insurance, HOA, etc.). If you do receive a seperate bill for real estate taxes or HOA, you pass those along to your mortgage holder (assuming they are also managing your escrow account), and they will send a check from your escrow account to these agencies.