Combobox Data Capture From Other Workbook

how data capturing works, using controls. I try to explain what I mean. I have a userform with a combobox that allows to select data from a worksheet in another workbook (database). Using VBA, I'm asked to define the "source" for the combobox. I don't understand the difference between controlsource and row source because when I close the userform, I find only the first field filled in (column "A"), while I would like the entire row to be copied.I also would like to have an "ok" button to allow me for multiple selection. In other words:

I select the desired data from the combobox
I click on the "ok" button ahd this event should copy the data (entire row) selected via the combobox on my worksheet without closing the userform in order to allow me to select other data on the same session. The row to copy data into is selected using the firstemptyrow method..