Populating My Userform Boxes with the Data I'm Editing

Right now I have a form where the user chooses an event from a combo box, types the start day (mm/dd/yyyy) and end day (mm/dd/yyyy) and types comments in a text box. I made it so the user could double click on previously created events and edit them, but the form shows up blank. How can I have the form open with the data that is to be edited showing up in each of the boxes?

It seems to me you only need to edit the cells on the sheet to make changes.
but to use a form,
(open form)
cboBox = activesheet.Range("A2").value
txtBox = activesheet.Range("A10").value

The problem is that the range is always changing. If someone enters 09/01/2015 as the start and 09/10/2015 as the end, (the way my sheet is set up) the range (activeCell.Row, column AG) - (activeCell.Row, column AP) gets highlighted. If someone enters a different date range, it could be on a different row and different columns. I don't actually save the dates in a specific cell.