One of the hardest things about teaching is trying to make the most out of the instructional time we have with our students. One of the easiest ways to do this in a meaningful way is to create a scope and sequence for each grade.
Starting at the End
There's no way you are going to be able to properly sequence your lessons if you don't have a clear set of goals for each grade to meet by the end of the year.
When I was developing my overall scope, I made a list of all of the rhythmic, melodic, and other concepts that I wanted my students to be able to understand at the end of the year.
Once you've created your end goal, now it's time to work backwards. I divided a piece of paper into each of the months we are in school and then filled in things like concerts and other special things that I know happen every year.
I then worked backwards from the end of the year and filled in the concepts and composers that I wanted to teach spread out across the year.
Make sure that your sequence builds upon itself. For example, if you want your students to be able to notate the rhythm to a known song using Ta, Ti-Ti, and Quarter Rest, then you want to make sure the students are able to have time to work with just Ta and Ti-Ti before adding in a rest.
Let it Evolve
This scope and sequence will change. It'll go through many iterations as the year goes on. But that is totally fine!
You want your curriculum scope to be flexible so that it can be adjusted to better fit the needs of your students. Depending on your students, you might need more time on a specific concept than you thought. Conversely, your students might be ready to move on to the next concept sooner than planned.
This is fine. Let your scope and sequence evolve to best fit your students.
Don't try to force a sequence on your students. Instead, let the sequence ebb and flow in a way that empowers your students to be active music-makers.