Need more information than that. What's the video about?

Thanks for your prompt reply.. Just find it  the sub form in continuous form via extended oneK ( sorry for the modal .. it doesnt use the modal property) but my question is I have a form(purchasing form) with the Purchasing and Product.. and I have use the PurchaseID to open a PRoduct form for check every item selling information(status) ,but the PRoductForm could not rolling according to each item in the Purchasing Form. How could I do?

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For your question I'm not sure about what you are asking exactly.  I think you need to watch the Invoicing video.
Especially the extended cut.  Because you are a Gold Member you can also download the example database and study the way things are done.  Not just in this video but all of the TechHelp videos.

Thanks for your prompt reply..
I have study for the invoicing video for several times'Klet me simply describe my situation:
Two table (purchase  and product ) to bind the purchase form (both continuous form) and  another for for check the purchased item is Product form( product item-singleForm and product selling detail-continuous form) .
I use the FirstForm-PurchaseID to open the Second Form and let the secondform modal for simultaneously checking via productID in the first form. But it didn''t work. That''s my problem is 'K
Though it might be so complicated'Kfor me.. 😂