Something like this might get you going:
Names Default To Here(1);
dt = Open("$SAMPLE_DATA/Big Class.jmp");
new = new window("",
rep = dt << get as report;
);
tb = rep[TableBox(1)];
tb << Set Scrollable(30, 4);
show(tb << Get Locked Columns);
tb << Set Locked Columns(2);
show(tb << Get Locked Columns);
<< get as report creates table box of datatable, get reference to that and then do modifications you want.
-Jarmo