docs: add KeptnApp reference in getting started (keptn#2202)

Signed-off-by: Griffin <prakritimandal611@gmail.com>
Signed-off-by: Prakriti Mandal <98270250+prakrit55@users.noreply.github.com>

docs/content/en/docs/getting-started/_index.md

@@ -469,11 +469,116 @@ View the Keptn Applications Dashboard and you should see the DORA metrics and an
 
 ## Step 14: More control over KeptnApp
 
-You may have noticed that the `KeptnApp` Custom Resources are created automatically by Keptn.
+To customize workloads and checks associated with the application, we can edit the autogenerated KeptnApp or create our own.
+
+```yaml
+apiVersion: lifecycle.keptn.sh/v1alpha3
+kind: KeptnApp
+metadata:
+  name: <app-name>
+  namespace: <app-namespace>
+spec:
+  version: "x.y"
+  revision: x
+  workloads:
+  - name: <workload1-name>
+    version: <version-string>
+  - name: <workload2-name>
+    version: <version-string>
+  preDeploymentTasks:
+  - <list of tasks>
+  postDeploymentTasks:
+  - <list of tasks>
+  preDeploymentEvaluations:
+  - <list of evaluations>
+  postDeploymentEvaluations:
+  - <list of evaluations>
+```
+
+## Fields
+
+- **apiVersion** -- API version being used.
+- **kind** -- Resource type.
+   Must be set to `KeptnApp`
+
+- **metadata**
+  - **name** -- Unique name of this application.
+    Names must comply with the
+    [Kubernetes Object Names and IDs](https://kubernetes.io/docs/concepts/overview/working-with-objects/names/#dns-subdomain-names)
+    specification.
+
+- **spec**
+  - **version** -- version of the Keptn application.
+    Changing this version number causes a new execution
+    of all application-level checks
+  - **revision** -- revision of a `version`.
+    The value is an integer that can be modified
+    to trigger another deployment of a `KeptnApp` of the same version.
+    For example, increment this number to restart a `KeptnApp` version
+    that failed to deploy, perhaps because a
+    `preDeploymentEvaluation` or `preDeploymentTask` failed.
+    See
+    [Restart an Application Deployment](../implementing/restart-application-deployment/)
+    for a longer discussion of this.
+  - **workloads**
+    - **name** - name of this Kubernetes
+      [workload](https://kubernetes.io/docs/concepts/workloads/).
+      Use the same naming rules listed above for the application name.
+      Provide one entry for each workload
+      associated with this Keptn application.
+    - **version** -- version number for this workload.
+      Changing this number causes a new execution
+      of checks for this workload only,
+      not the entire application.
+
+The remaining fields are required only when implementing
+the release lifecycle management feature.
+If used, these fields must be populated manually:
+
+- **preDeploymentTasks** -- list each task
+    to be run as part of the pre-deployment stage.
+    Task names must match the value of the `metadata.name` field
+    for the associated [KeptnTaskDefinition](../yaml-crd-ref/taskdefinition.md) resource.
+- **postDeploymentTasks** -- list each task
+    to be run as part of the post-deployment stage.
+    Task names must match the value of the `metadata.name` field
+    for the associated
+    [KeptnTaskDefinition](../yaml-crd-ref/taskdefinition.md)
+    resource.
+- **preDeploymentEvaluations** -- list each evaluation to be run
+    as part of the pre-deployment stage.
+    Evaluation names must match the value of the `metadata.name` field
+    for the associated
+    [KeptnEvaluationDefinition](../yaml-crd-ref/evaluationdefinition.md)
+    resource.
+- **postDeploymentEvaluations** -- list each evaluation to be run
+    as part of the post-deployment stage.
+    Evaluation names must match the value of the `metadata.name` field
+    for the associated [KeptnEvaluationDefinition](../yaml-crd-ref/evaluationdefinition.md)
+    resource.
+
+## Example
 
-The lifecycle toolkit automatically groups workloads into `KeptnApp`s by looking for matching
-`app.kubernetes.io/part-of` annotations.
-Any workloads with the same `part-of` annotation are said to be `part-of` the same `KeptnApp`.
+```yaml
+apiVersion: lifecycle.keptn.sh/v1alpha3
+kind: KeptnApp
+metadata:
+  name: podtato-head
+  namespace: podtato-kubectl
+spec:
+  version: "latest"
+  workloads:
+  - name: podtato-head-left-arm
+    version: "my_vers12.5"
+  - name: podtato-head-left-leg
+    version: "my_v24"
+  postDeploymentTasks:
+  - post-deployment-hello
+  preDeploymentEvaluations:
+  - my-prometheus-definition
+```
+
+You may have noticed that the `KeptnApp` Custom Resources are created automatically by Keptn.
 
 However, you can override this automatic behaviour by creating a custom `KeptnApp` CRD.
 In this way, you are in full control of what constitutes a Keptn Application.