fn-option-<function key>
then
fn-command-<function key>
yes, it takes both combinations for one function key. so, for example, to use f12:
fn-option-f12
fn-command-f12
page up & down are similar:
fn-option-<up arrow>
then
fn-command-<up arrow>
fn-option-<function key>
then
fn-command-<function key>
fn-option-f12
fn-command-f12
fn-option-<up arrow>
then
fn-command-<up arrow>