What is the Projects hierarchy for non-development work?

What is the Projects hierarchy for non-development work?

I am a marketing manager attempting to use Zoho Projects to keep track of content creation, design, website, and campaign projects. I'd like to understand the hierarchy of the following components: 

- Project
- Task
- Subtask
- Issue
- Task list
- Milestone

For example, I need to create a "project" in Projects for an email campaign due to go out on 12/30/20. In the "project" I need to assign the following steps to various people on my team: 
  1. Schedule meeting with experts
  2. Write an article from meeting notes 
  3. Design flyer for article
  4. Publish the article on the website
  5. Design Email Campaign
  6. Design Social Banners about article
  7. Schedule Social Banners
  8. Schedule Email 
What should the "project" be if I have tons of these campaigns on top of other marketing projects on a platform where other teams work? I was using a Task List for each "project" but it doesn't have a due date associated with it and I can't view it on the calendar. Then I started using Issues for each "project" because they show up on the calendar only by due date, but I can't view the tasks in each issue as a list (I have to go into each issue and click into the tasks). 

Now with the milestones, I thought that could be a good thing to use for "projects" but I don't have a task list for that either. 

Yes, I would use a Project for each of my "projects" except that I do need some overall organization (i.e. Marketing Campaigns vs. Corporate Requests vs Digital Marketing). 

What do you all suggest? I wish I had the option to view tasks in the Calendar view by duration or I have no option to view it by due date, instead it shows the entire duration of the task.