Adding / Creating Collection using Event "Selection Change [Interactive Grid]"

I am trying to do this for the first time. I would like to add a column (order number) of an Interactive grid to a collection when I select the row. I have setup a simple interactive grid just querying the oe_headers_all and oe_lines_all tables, then added a column with the type of "Row Selector." It seems like it should be simple but everything I find for creating a collection is coming from a database table. Anyone have any tips / tutorials / APEX Blogs that could help?

I am on 18.2

Thanks,

Chris