Starting CS Fundamentals for all Grades at once

Hi, I will be trying to implement coding in my primary school for the first time.
Do the Course A-F run concurrently and do you have to start with A or can you place each grade in a course based on the suggested Grade provided without completing the previous course?

Thanks for the assistance

Hello there! I am teaching coding to the elementary schools in my district TK-5th grade. I started every grade a grade below: Kinder is doing course A but I supplement with other activities the first half of school year so now they are just getting into the online lessons. Grade 1 is doing Course A, Grade 2 is doing Course B, etc. Most of all students hadn’t had prior coding experience so I thought it would be best to the grade below. I am glad I did. I see it’s working out really well! I think next year I will keep it the same way too. I see each class 1st grade through 5th once a week for 25 minutes, TK/K is once every other week. It usually takes 2 days to do most lessons. I think going forward next year some lessons will be finished faster now that they have had prior experience.