Zephyr's Defect Tracking application can be found in all the Desktops - Test Manager, Test Lead, Tester and Defect User. Irrespective of which Defect Tracking System is chosen in the Administration application (currently "Internal", "Bugzilla" or "JIRA"), the user interface remains the same. If no system is selected, then this application will not be displayed in these Desktops.
Defects can be opened in 2 ways:
On opening the application and selecting the "New" tab
In Testcase Execution, if the status of a testcase has been changed to "Fail", a "Defect" button pops up. Clicking on that "Defect" button will allow the creation of a new defect.
If the Defect Tracking System chosen in the Administration application is Internal, the following screen is displayed:

The following defect fields are shown when creating a new defect:
Subject: This is where the subject or the title (or a 1-line summary/description) of the defect is entered. Its a mandatory field.
Tags: This is where the tags from a testcase are carried over if a defect is associated with a testcase. This field is populated automatically.
Alt ID: This is where the Alternate ID from a testcase is carried over if a defect is associated with a testcase. This field is populated automatically.
Description: This is the long/detailed description of the defect. Updates to the defect are added here too. This is a mandatory field.
Attachment: Multiple attachments can be added to a defect. The defect must first be saved before an attachment can be added to it. This field is not mandatory.
Priority: A drop-down list of P1-P5. This is a mandatory field.
Status: This field is initially populated automatically but then has a drop-down to change states based on the workflow assignments. The states are New, Assigned, Fixed, Reopened, Verified, Rejected, and Closed
Assigned to: This is a mandatory field and it contains a drop-down of users of the system and based on the allowable state changes, default values are shown.
Project: The Project drop-down shows a list of projects for which defects can be filed. This is a mandatory field and must be picked first so that it unlocks the other related fields (Component, Version, Severity, Priority).
Component: The Component drop-down shows a list of pre-set components that belong to a particular project. This is a mandatory field.
Version: The Version drop-down shows a list of Releases/Iterations that are specific to the Project selected.
Severity: The Severity drop-down has the following pre-set values: Fatal, Major, Minor, Trivial, Suggestion, and Blocker. This is a mandatory field.
Custom Field 1: This is a customizable field ("Environment" in this example) that can have values in a drop-down that is set in the Defect Admin application.
Custom Field 2: This is a customizable field ("Browser" in this example) that can have values in a drop-down that is set in the Defect Admin application.
If Bugzilla is the defect tracking system being used, filing a defect has the following screen:

The following defect fields are shown when creating a new defect:
Subject: This is where the subject or the title (or a 1-line summary/description) of the defect is entered. Its a mandatory field.
Tags: This is where the tags from a testcase are carried over if a defect is associated with a testcase. This field is populated automatically.
Test Case ID: This is where the Alternate ID from a testcase is carried over if a defect is associated with a testcase. This field is populated automatically.
Description: This is the long/detailed description of the defect. Updates to the defect are added here too. This is a mandatory field.
Attachment: Multiple attachments can be added to a defect. The defect must first be saved before an attachment can be added to it. This field is not mandatory. Once added an attachment cannot be deleted, only replaced.
Priority: A drop-down list of P1-P5 and they come from Bugzilla. This is a mandatory field.
Status: This field is initially populated automatically but then has a drop-down to change states. The states are New, Assigned, Fixed, Reopened, Resolved, Unconfirmed, and Closed and they come from Bugzilla
Resolution: This field has a drop-down with values of Fixed, Invalid, Wontfix, Later, Remind, Duplicate, Worksforme, and Moved. These come from Bugzilla.
Project: The Project drop-down shows a list of projects for which defects can be filed. This list comes from the association in the Project Setup application.
If Bugzilla is the defect tracking system being used, filing a defect has the following screen:

The following defect fields are shown when creating a new defect:
Subject: This is where the subject or the title (or a 1-line summary/description) of the defect is entered. Its a mandatory field.
Tags: This is where the tags from a testcase are carried over if a defect is associated with a testcase. This field is populated automatically.
Test Case ID: This is where the Alternate ID from a testcase is carried over if a defect is associated with a testcase. This field is populated automatically.
Description: This is the long/detailed description of the defect. Updates to the defect are added here too. This is a mandatory field.
Attachment: Multiple attachments can be added to a defect. The defect must first be saved before an attachment can be added to it. This field is not mandatory. Once added an attachment cannot be deleted, only replaced.
Priority: A drop-down list of P1-P5 and they come from JIRA. This is a mandatory field.
Status: This field is initially populated automatically but then has a drop-down to change states. The states come from JIRA.
Resolution: This field has a drop-down with values that come from JIRA.
Project: The Project drop-down shows a list of projects for which defects can be filed. This list comes from the association in the Project Setup application.