What is the best practice how to go through Optional Labs?

Actually I likely need to add that when I open Jupyter Notebook for the first time I already see the code in code cells beneath the markdown instructions. Is this the intended behavior?

Since I have another question about possibly being routed to someone other’s space and then likely seeing/opening someone other’s files, is it my correct guess that code cells should be empty and I should place the code there myself if I am using the correct files addressed to me personally in this course?