How to get multiple record or selected record in D365FO

Public static void main(Args _args)
{
ProjOnAccTrans  projOnAccTrans;
        FormRun formRun = _args.caller();
        FormDataSource fds;
        fds = formRun.dataSource(formDataSourceStr(ProjTransOnAcc,ProjOnAccTrans));

        projOnAccTrans = fds.getFirst(true);
}