I had many plants in my front yard and I was working out there often...this year I bought some annuals and some perennials and put them in pots (you can use cheap plastic pots) and place them wherever you want. The thing I like about the pots is that if it's a real hot year you can move them around...same if it's a rainy summer you can place them in sun and let them dry out. You can put them on a porch, try them in different spots to see how they look, try different types of plants each year and they add beauty all over. As you take care of your plants you will learn about different types of aphids, slugs, worms that invade plants. When you feel you have enough knowledge where you're comfortable then begin planting in the ground. Good luck....it's a lot of work but a wonderful reward. Buy a book to begin learning about the plants you have, what colors recede or pop right out, all different things.
Marigolds are easy. If you decide to plant any bulbs for tulips or such you should know that they have a top and bottom and if you plant them wrong they won't grow up to where you will see them. Hostas are very nice plants but they attract slugs,
Look at the flowers that grow wild in your area, they would be a good place to start because they survive without any help from us.