It can be scary to set up a curriculum for homeschooled kids. However, it doesn't need to be complicated. There are many complete, economical resources that can help you. Most of the work is already done.
You should have a list of subjects that you will be teaching. Keep in mind that middle school students and preschoolers may need different lists. Kindergartners and preschoolers work with letters, numbers, and shapes. Grammar school students learn Math, Reading, and Writing, Art, History, and Music, as well as Science. You can also get complete curriculum workbooks at Popular Book Company (USA) Limited.
Middle school and high school students are offered life skills, advanced math, specialized science, and many other classes.
Check your state's standards
While there are national standards, you should also review the educational standards in your state for each grade you have students. Search for the Department of Education in your state. Once you are on the website, search "science standards" or "math standards", and other subjects.
For example, I'm in Colorado with two fourth-grade math students. These skills are listed on the website:
Whole numbers and fractions What do they mean? What are their uses?
Number order and place value (Where is the 4 in 4,123?) Are they units, tens or hundreds of thousands? Which is greater? Which number is greater? 4,523 or, 4,532? Use numbers for measuring, counting, and ordering.