Macro Help - Newb here... Creating Table

Hey All,
So i'm definitely not smart with this stuff (which is why I'm coming to you all!)

Here's what we're trying to do. We have a single worksheet and need to keep it on one sheet. The top "table" will be edited by the user. They will have the ability to insert rows and the data as necessary. Below this user-defined table we need two tables that separate the data that was collected.

I'll try to explain this as best as possible and have attached the document as well.

The table that people have the ability to edit/add to contains a model number, description of the item, total quantity of item sent, and the total quantity of that item they would like to return. The macro will need to separate the items by the quantity of items staying vs. the items being returned. The return table should just pull values from the "Return Qty" column (Column E). The Items Staying table will need to do a simple subtraction of Column D minus Column E (Qty minus Return Qty).

I have searched many forums and spent too much time on the interwebs and I'm getting frustrated. Was hoping to find a similar code that I could manipulate to my needs, but again, I suck at this. My big hang up is the fact that people will have the ability to ADD rows to the user defined table. I was going to do some simple formula (if/then statements) to just copy data down, but that ability to add tables makes me feel like the macro is needed.

Any of you able to help out??