Welcome to our world! One of the most wondrous things about gardening is that it's not permanent. Plants can be moved. I know how you're feeling .. like a deer in the headlights! All these plants and what to do with them. You will never be finished with your garden. It's an ongoing project forever.
Start off with looking at other gardens and how they are laid out. I'd be willing to bet there are a number of books on landscaping in your public library. They will give you ideas on how to put it all together.
One way to keep from being overwhelmed, divide your space into rooms/sections and go from there and start off with plants in containers so they are easy to move around. Through experience you'll find out what works and what doesn't work for you. And as I said, plants are very movable. I have one Confederate Rose that had been dug up and moved 8 times before I finally found a place that worked for it and me.
Gardening is purely subjective.
