You want the easy way? Install the More Fields plugin and create your custom field using that. One of the field types is a datepicker: select that when creating the custom field and you’ve got a datepicker.
Other plugins of interest:
You want the easy way? Install the More Fields plugin and create your custom field using that. One of the field types is a datepicker: select that when creating the custom field and you’ve got a datepicker.
Other plugins of interest: