I want to plant a garden but idk how to start. I live in Az and the dirt is really dry here. Where shld i start and what steps do i have to take to plant herbs and flowers and stuff in terms of compost and fertilizer and mulching uh there is so much stuff! any tips or good products to use?

Dowlingg has good tips, but in Arizona you will likely need at least 6 inches of mulch to:
1) Keep the soil wet during the hot, dry days.
2) keep the roots from burning and killing the plant.

You might want to put the garden that gets 100% shade all day, or only 2 hours of sunlight. It’s already plenty hot and dry down there.

Also, it might be illegal to use city water to irrigate your garden. You might have to get a rain barrel. Contact a lawyer or ask some neighbors how they water their gardens.

There are not many veggie plants like prefer hot, dry conditions. Most of those like moist conditions, not too hot.