checkbox on interactie list

Hi guys,

I'm creating a report where in it could display the details of a selected record/s for printing. In selecting a record you have to tick the checkbox and click display icon on the application bar.

how will i do that?

I already did it in in user-command, where in sy-ucomm = display it will read table lt_header with key check = 'X'.

but I dont think it doesn't get the selected record.