I'm following directions from a book Odoo 12  Dev essentials 

Chapter 1
I have successfully gone through :
*Adding a field to a Model

and now at 

*Adding a field to a form view

"...A pop-up window, Create Views which inherit from this one, will be shown, and we should fill it with the following values: "

View Name: Contacts - Custom "Is Work Team" flag

Architecture: Use the following XML:

<field name="category_id" position="after">

  <field name="x_is_work_team" />

</field>

then the book goes on to state "...the other important fields, such as the Model, View Type, and Inherited View, already have the correct default values..."

Default values?? they are empty

moving on...

The above code does not work...
it breaks  until I fill in the values like so

View Type -> Form 

Model-> res.partner  

and change the Architecture to

<form string="Partners">

  <field name="category_id" position="after">

      <field name="x_is_work_team" />

  </field>

</form>

then save and reload but nothing happens

whats the right approach of adding a simple boolean field  to a preexisting view

this is the link of what Im following
https://subscription.packtpub.com/book/business/9781789532470/1/ch01lvl1sec14/modifying-an-existing-model-to-add-a-field