Hi @leuchterits
You need to create a field group or add new custom fields to hold the first and last name. If you create a new field group, you can show it like this:
acf_form(array(
'field_groups' => array('99'),
));
Where ’99’ is the ID of the field group. If you add new custom fields to the existing field group, then you don’t need to change anything.
I hope this makes sense 🙂