Esperanza-- did you buy "garden soil?" That should be mixed with native soil, usually 50/50.
Squash are super easy to grow. Watermelon aren't. You don't have to buy/build a raised bed if you don't want to. You can dug up the turf/lawn (that's the hard part) and then turn the soil, mixing in the garden soil. West facing is good! Both squash and watermelon need full sun.
We've planted lettuce, kale, spinach, tomatoes, peas, snow peas, cucumbers, and dill. We already had asparagus, raspberries, blackberries, strawberries, blueberries, apples, and cherries. Hoping to find tomatillo plants. Those did really well last time and were so yummy.
I didn't get tanglefoot on my fruit trees in time
so I'll be spraying neem oil all season.
The moose like to eat my cherry tree.
Oh, I also have a grape vine! It's not that big yet but I'm expecting grapes this year.