In the Disney.com site to go to resturaunts/discover/dining/ all the resturants come up you can sort by park/resort etc. or list all.
Then you select the one you want to see if there are opening for when you want. The ones that req ressie say book a res. You can play with dates there and choose your dates and party size and times. If it is not available they may offer you options.
If you find what you are looking for you just select it and you will get a confirmation #. I always write it down and They also send an email as well.