As a document grows over time and in scale, code accumulates, as does process (such as import form other apps).
Whilst actual action code can hold comments, it is also worthwhile making some notes about overall process. Ideally store these notes away from the document working content, and capture enough detail to inform future self or collaborators as the the overall intent if the automation in the process: why code/functions were added, the steps to do certain processes, etc.
These notes will repay in any latter debugging in the note.
Do update the notes as the document ensures, so that they are not out of date when/if needed for future reference. It is much easier to capture this information at the time the process is implemented than trying to remember detail later.