Retrieve data row after filling in BAQCombo

I’m working in a UD100 form where the user will choose from a BAQCombo to begin. The combo returns the Key2 value from the UD100 table. Once this is selected, the form should auto-fill as if the user used the built-in search box, which uses the Key1 value to search. For example, if I opened the form and clicked on the search box, I’d select a row from the search results and the form would auto-fill with the information from that row.

How can I make that happen after selecting from the BAQCombo?

The BAQCombo I’m testing is on the right of the search button. That will show all models, which are Key2 values. After selecting from the dropdown, the form should auto-fill as if selecting from the search menu.