sandbox v. live discrepency

Ok so I have attempted once again to understand some things with Wix and I hope you can help me further because I’m about ready to just give up and give my users access to an Excel spreadsheet in Box.com and call this over. Also note as I said in another post, no wix coding people are responding to my call for help of paying them to provide me the answers for me to plug into my site.

So what I have is the following:
The Player input data page Submit Game Played Form shows the fields of the collection that are needed to be shown to the user.
Each line item is populated on the page when a user fills out the data entry items and if they like they can submit a summary document using the upload button then click Submit.
When they click Submit, the data is sent to the “live” sandbox collection (therefore what is showing in the working sandbox collection itself is now obsolete, so only the “live” sandbox data matters).
So my next issue is this:

How can I:
---- click on a line item in the table and
-----have that data load into the data entry fields (therefore queued up and standing ready to be updated/changed), when
------the Update button is clicked.

You see, right now, each time a user enters data into the data entry fields and even before they click Submit, when they leave a data entry item for the next one it ADDS that information to a new line of the table. This is fine for adding a “record.” But then I want to
---- click on that line item “record” and have the data of that row populate the data entry fields for the user to change at will then click and Update button to have that new data replace the old data of that “record” without having to goto another Get and Modify page.

I hope I have been clear. What tutorial do you know of that will answer this scenario, because the ones I have tried have just not done it for me. Yes I need to be spooned in order to get it right the first time and then continue using that work as a model for other db to come.