1. Create a new method on form and copy the following code.
2. Next create a button on form . and call the method on the button click event.
(for the button property makesure the Multiselect should be set to yes , or else by default for multiple selection system will disable the buttons)
//getFirst method gets all the selected records in the grid
inventLocal = InventTable_ds.getFirst(true);
info(strfmt("You selected Item %1",inventLocal.ItemId));
// get the next selected record
inventLocal = InventTable_ds.getNext();