Need ETA report based on items ordered and suppliers

I am trying to make a ETA report based on a list of orders to be filled and a list of items ordered from suppliers.
Below is a picture of both forms, left is orders to be filled and on the right form is items ordered with eta to fill orders on left form.
Capture1.PNG

I have been manually going through line by line and filling in the items eta, example below:

Capture2.PNG

I'm pretty good with formulas, but this is beyond me; I need to be able to do this formula driven because the lines I manually go through now are over 1300.

2 things.

Administrative Note:

Welcome to the forum, knowchild .

We would very much like to help you with your query, however the thread title does not really convey what your request is about. Tell us what you are trying to do, not how you think it should be done.

Please take a moment to amend your thread title. Make sure that the title properly explains your request. Your title should be explicit and not be generic (this includes function names used without an indication of what you are trying to achieve).

Please see Forum Rule #1 about proper thread titles and adjust accordingly. To edit the thread title, open the original post to edit and then click on Go Advanced (bottom right) to access the area where you can edit your title.

(Note: this change is not optional. No help to be offered until this moderation request has been fulfilled.)

Since you are new to the forum I will change it for you this time.

Additionally please upload a sample workbook. Instructions are at the top of the page. HOW TO ATTACH YOUR SAMPLE WORKBOOK: