Start with one bed along a fence or the back of the house, not the whole yard. Clear the grass, spread 2 to 3 inches of mulch, and plant three to five hardy shrubs or perennials suited to your USDA zone. That single project teaches you soil prep, spacing, and watering without much risk, and a starter bed usually costs $150 to $400 in plants and mulch.
A few rules keep beginners out of trouble. Check your hardiness zone before buying anything. Plant in odd-numbered groups and repeat the same plant rather than collecting one of everything. Water deeply once or twice a week instead of a daily sprinkle. Add the next bed the following season once the first one has settled in.
If you want a target to work toward, generate a few finished looks for your yard with AI backyard design first.