Hi Ben,

If you need “sort of” more help, you need to explain to us a bit more next time. Creating CPTs and attaching categories to it are usually simple tasks.

You mention that you have created your own CPT using a plugin, which plugin are you using? (wp-types, Custom Post Type UI??). Check on your plugin if you have an option to add taxonomies. If they do, you can added directly from there.
Do you want to create a custom taxonomy or simple use the default wordpress taxonomies?

If you want to create your own taxonomy (categories or tags) the wordpress way, then check this website: http://generatewp.com/taxonomy/
and check this line!
register_taxonomy( 'taxonomy', array( 'YOUR_OWN_CPT' ), $args );

Interesting question. I really have no idea, try maybe something like:

1. Get the list of categories
2 Use piklist condition and add your list of categories in a select or checkbox field
3. Then use the value field to compare it with the value selected in the list.

ex:
$list = your_categories

piklist(‘field’, array(
‘type’ => ‘select’
,’field’ => ‘my_categories’
,’label’ => ‘Would you like to subscribe to our newsletter?’
,’attributes’ => array(
‘class’ => ‘text’
)
,’choices’ => $list /*Look at the format*/
));

piklist(‘field’, array(
‘type’ => ‘text’
,’field’ => ’email_address’
,’label’ => ‘Email Address’
,’description’ => ‘Please enter your email address’
,’conditions’ => array(
array(
‘field’ => ‘my_categories’
,’value’ => ‘the_conditional_category’
)
)
));

Anyways, try something like this
Good Luck