Welcome to the forum.
When working with Autocad you ALWAYS draw everything at full scale 1:1, in your MODELSPACE.
That is true whether you are doing subatomic studies, or astrophysics.
You will later apply whatever scale is appropriate by using a VIEWPORT in PAPERSPACE to scale it onto your sheet for printing.
You may find this previous post by ReMark informative.
If that was news to you, then you might do well to watch the following video too.
The instructions, as you describe them sound strange.
Was that your interpretation of them, or do you have any written instructions for this exercise from your instructor?