You can either use it as a mulch "top layer" or you can dig it into the ground before planting something. If you dig it in you improve the soil more then if you just use a top layer, but if you have plants already there you don't want to disturb their roots too much.

And it won't matter that I'm doing it a year in advance, right? The soil will still be good and healthy next year if I start digging it in now?

The longer ahead you work with the soil the better the soil will be. It takes many years to build a quality soil. It is really much better to do your soil prep months in advance before planting to give the soil a chance to improve. But each time I put in new plants, I always add compost which I mix with the native soil. Always mix the native soil with the compost, never just dig a hole and put in compost and plant there. The plants will do very badly. Mixing as far down as possible insures even drainage.

If the alternative is leaving it in a compost pile, it does a lot more good in the ground even a year ahead. As soon as it is mixed in, a whole process begins on a microscopic scale to incorporate the organic matter and nutrients into the soil structure. This goes on for a long time. So yes, it will help even a year ahead. Put more in right before you plant, if you can.

If you just leave in the compost pile it will go away eventually, but if you did it in the ground it will improve the soil. Although it will improve the soil, it will only improve the soil directly under the pile, if you never take it out. Some people may wish to just recycle yard waste. That would be a lot less work, come to think of it.

Thank you guys so much for your help! =]

I had a truck load of horse manure dumped near a field to rot
& changed garden spots because there was no water near it.
The straw & manure rotted with none of the composting rule being used, I did not turn it. Next spring I walked up to the pile & found it was 1/4 the size when I dumped it & rotten finished compost. I forgot about it & ran up on it months later, then again even later. It seemed to melt away like snow. I was 18, new to composting & had the run of my Father farm. Point is the compost will waste away if not kelp in a bin or used in the garden.

Even in a bin, unless it is completely dry and kept that way. But then it's kind of dead.

I would describe the process as a very steep curve at the beginning (high microbial activity and fast volume reduction), followed by a looooong tail that will eventually make a pile nearly disappear. Compost is usable on most of this curve (even at the very beginning if ingrediennts are mixed up and used as a mulch). It is better to put it to work for your soil and plants sooner than later.

The only time I save finished compost is in a bag over the winter so I have something to plant my very early veggies with while the piles are still wet or even frozen.

I second that opinion, the sooner you it the better. The longer you wait the less you get and there is never enough compost. That is why everyone needs two bins, one is the store finished compost where it will continue to break down. There is nothing worse then you want to go plant something and you have no finished compost on hand.