To build a garden you first want to think about where to plant it. You want to make sure it's away from trees and buildings and close to your home and water. Think about the area with th best soil and whether it will be big or small.
Your best bet is to go small. You need to think thats more you have to hoe and water. You want to locate it where it gets the most sun. Next you want to test the soil. If your squeeze it and it is crumbly then its good but if it doesn't crumble then you want to add compost.
You want to make sure your garden is protected. A wire mesh will work best. You want to make row for you plants. They grow better with more room. You want to have fresh new seeds. They grow they best.
You want to water you plants regularly. Make sure they get at least 1 inch a week. You don't want to over water them either.
So now that you have your garden ready. Just take good care of it. Make sure you check ot everyday.