BuddyPress.org

Hello, i want the same to hide the mention and favorite tabs.. But i dont now how to past the code:
function bp_remove_sub_tabs() {
if ( ! bp_is_user() ) {
return;
}
bp_core_remove_subnav_item( ‘activity’, ‘mentions’ );
bp_core_remove_subnav_item( ‘activity’, ‘favorites’ );
}
add_action( ‘bp_actions’, ‘bp_remove_sub_tabs’ );

On the theme editor? can you tel me how to do that ? i have never yet done that..
I hope you can help me..
Kind regard vd Hee