The link is giving steps which are valid for an older version of Pega (7.2.1). In 7.3 layout tab is not available while configuring the view. You can update the view directly at runtime. That will give you a WYSIWYG UI authoring experience. For that, you can follow the below steps.
Make sure editing is on.
Select a case type name from the + New menu to create a case.
Reach the collect info step which you would like to edit
Click on Configure this view which is shown with a small pencil icon.
In the right panel, click Change template to switch the existing layout to any of the standard or custom predefined design templates.