Hello, love Las Vegas! Lately it's been so hot here in East County San Diego, it feels like Vegas. While I have no idea what would work for you, when I began my garden I relied a lot on the wonderful articles posted on Houzz by pros. Start here and see what grabs you. http://www.houzz.com/ideabooks/Gardening

For vegetables this fall, any of the green leafy ones,
like Bok Choy, spinach and chard will grow all winter and are pretty
frost-tolerant id you start them real soon. The trick with compost is amend one area WELL instead of spreading it thinly. Consider using raised or at least confined beds for the vegetables and amending it thoroughly.

Figure out what to do for watering. Ideal is a drip system on a timer. If one exists, you can convert one or more sprinkler stations to drip tubing by capping some of the sprinklers and using drip adapters on the rest.

If the back faces EAST you will have afternoon shade for things close to the house, and afternoon or all-day sun for the things further away.

For near-instant shade, how about an arbor or hefty trellis with vines. The first year, plant perennials AND annuals to fill in. As the perennials get established, you can plant fewer annuals.

ANNUALS: late spring-planted snake gourd (Armenian Cucumber) loves heat and will cover a trellis and give you shade with cucumbers all summer.

This is "Queen's Wreath" (Antigonon leptopus) after several years growth. It is held up by concrete remesh wire over the crossbars. Our Armenian Cucumbers had about the same coverage, but with cukes dangling through the mesh.

a mister system installed in remesh might help too since it is so dry in Vegas,depending on what you want to grow. Careful not to overuse it so it doesn't cause any type of fungus or rot. Cantalope grow well in the arid climates and fast.Peas(place a pea seeds in an ice cube tray fill with water freeze then plant the whole ice cube).Mammoth sunflowers these have the gray&white stripe seeds you get at stores to eat. Planting marigolds or other flowers help with bugs. Mix them in amoungst the veggies. Perennial herbs such as Rosemary grow well in arid conditions. Be careful to watch for scorpions in your compost, and garden. Corn grows well in sun too. A lot of these plants can also be reused/replanted by collecting the seeds they produce, just let some of them stay on plant after ripening until they dry. Collect the seeds keep them dry and marked stating when they were harvested,what they are or what colors they are if they are flowers or different varieties of the same veggie. For pest control go online and order ladybugs(chuck@highsierraladybugs.us) or praying/preying mantis egg cases. You can also add beneficial nematodes or add natural,organic fertilizers containing Endomycorrhizae,Ectomycorrhizae and beneficial bacterias. Jobes(I do not work for them) makes a good inexpensive brand. It is called Jobe's Organics Natural&Organic Fertilizer. I even use this in all my houseplants and cacti garden. I have a huge house plant that I have kept alive for 45 yrs. with the help of Jobe's stuff. Bone meal everything! Have fun, gardening is so fun and therapeutic too.

Visit Star Nursery. They have information up front in most locations that not only provide suggestions, but there is information regarding planting time, etc. I have grown veggies, but never from seed. Tomatoes and many root vegetables grow well. I also had great luck with broccoli, but in a sheltered position. The first thing you may want to do is check your soil, as it may need major amending before you are able to successfully grow anything in the ground.