To start your yard project there are a couple of thing you will need to think through before you ever pick up a shovel or purchase anything other than a magazine or book to solidify your ideas. Way to many people start a project only to find that they are in way over their heads or that there is not enough time in the day, weeks and months ahead to get the job completed.
I work with a guy that has two newly married sons with brand new older houses. Both boys have grown up watching their old man build, fix and make all kinds of things from a swimming pool to an acre garden and I guess they thought they inherited the fix it gene. My buddy has spent the last 6 months finishing up what the kids started. They had no idea what it would cost or the time it would take and they had the perfect person to ask; their dad.
You may not think you have someone close who can help you but there are plenty of hardware stores that can help you plan and some of them have classes you can take where you can learn some of the techniques and how to do what you want to do. Personally, I use the library and the internet. It is amazing what you can find in these two places.
Now take out a piece of paper and start drawing. Your not making the Mona Lisa so don’t worry that it is not to scale, etc.; you can get to that later once you have your plan down. Don’t spend too much time on looks but spend a lot of time on wants and staying within your budget.