I read this post and see that I need to create the following "keys" but it doesn't explain how to do this.:

'_day_of_1' => '{0} January, {1}',
'_day_of_2' => '{0} February, {1}',
'_day_of_3' => '{0} March, {1}',
'_day_of_4' => '{0} April, {1}',
'_day_of_5' => '{0} May, {1}',
'_day_of_6' => '{0} June, {1}',
'_day_of_7' => '{0} July, {1}',
'_day_of_8' => '{0} August, {1}',
'_day_of_9' => '{0} September, {1}',
'_day_of_10' => '{0} October, {1}',
'_day_of_11' see more => '{0} November, {1}',
'_day_of_12' => '{0} December, {1}',