Adding an additional field to every event

You do it the same way as you would adding extra fields to other post types:

1. Add action add_meta_boxes and define fields
2. Add action save_post and save custom data with add_post_meta() and update_post_meta()

Hope that helps!

You would do that in functions.php of your theme. A third step would be necessary:

3. Show field data in your template using get_post_meta().

But actually there is an more easy way, in the case you are not comfortable with php code. You could use WordPress custom fields.

You have to output the content of your custom fields in your template. So if you want to show “age range” on the event template, the easiest way would be to add this to your single-event.php:

the_meta()

This outputs all custom fields. If you want to output only one, you should do something like that:

get_post_meta( get_the_ID(), 'age_range', true );