I have a drop ship account set up with a company.
Basically you will need to manage orders incoming and creating the same orders to the drop shipping company. That will be your day to day after you set up the items in the various places.
I have both an amazon account as well as an ebay account I would make a list of items and my cost.
You need to then research the competing best selling same items and market them slightly under the price of the competitors.
It would be best if you have management tools for this type of work.
Your research will include finding images and descriptions for all the products.