Welcome to SaleHoo ANS :)
Good to see that you know where you are going with your business! IF you have subscribed to a dropshipper already then you should have no trouble in copying their product listing directly from their dropship site to your eBay store/listing. If you are experiencing any issues it is best that you contact your dropshipper directly so they can assist you or provide you with the correct steps.
You might also want to check with your dropshipper if they can provide you with an updated list of their product listings so you can do a bulk update to eBay by using tools such as Turbo Lister.
Hope this helps :) Please let us know how you get on.