I'm not sure they will start unless you get them from untreated trees. Most of the fruit in the stores are force ripened after being shipped green. It's done very quickly, using a gas. in effect, this sterilizes the seeds.
You might try fruit from a health food store. Actually though, I think they use the same process. Stuff is picked green, just before it turns, and then ripened as it's put on the trucks to be taken to the stores.
For apples, if you get a seed that isn't sterile, plant it 1/2 inch deep in well drained soil, and water well until it germinates. Once it's about 6 inches high you can transplant it outside into the elements, but keep it watered well for the first 6 months.
For peaches, these are a little trickier. You have to fool the seed into thinking the peach rotted around it, and that it's lying on the earth. Drill some small holes in four sides equal-laterally around the seed. Put some toothpicks in those holes. Make sure they're very shallow. Don't break the hard covering of the seed, just drill a very small hole that a toothpick can wedge into.
So now you have a peach pit with four toothpicks coming our of it like umm, flower petals... OK?
Now, take and balance your pit on a glass, and fill the glass with water until just the bottom half of the pit is covered with water. Keep it that way until the pit opens and starts to grow. Then you can transplant it into dirt.
Remember, this works only if the seeds aren't sterile. And honestly, I've never had the peach work. Avocado? Yes. Peach? No.
Dan