Add defaults to Zowe yaml configuration

docs/appendix/zowe-yaml-configuration.md

@@ -46,7 +46,32 @@ The Zowe YAML configuration file has template logic for relating one value to an
 It can help to make your configuration portable between systems that need slightly different behavior while retaining the same configuration file.
 More details can be found [in the configmgr documentation.](../user-guide/configmgr-using.md#configuration-templates)
 
-### Configuration override
+### Configuration override - defaults.yaml
+
+There is a [`defaults.yaml`](https://github.com/zowe/zowe-install-packaging/blob/v3.x/staging/files/defaults.yaml) file, which defines values for global configuration and components. This file is always merged with current config(s) when `configmgr` is used.
+
+For example, if you decide to remove `zowe.job` section by commenting or deleting, after the merging with the defaults the `zowe.job` section will be present again:
+
+**Example of user config:**
+
+  ```yaml
+  zowe:
+    # job:
+    # Zowe JES job name
+    # name: ZW3SV1
+    # Prefix of component address space
+    # prefix: ZW31
+  ```
+
+**Example of merged result:**
+
+  ```yaml
+  zowe:
+    job:
+      name: ZWE1SV
+      prefix: ZWE1
+  ```
+### Configuration override - inside zowe.yaml
 
 Inside `zowe.yaml`, you can define default values and they may be overridden in more granular level configurations. This can happen in several ways:
 
@@ -293,7 +318,7 @@ zowe:
 - `zowe.setup.security.groups.stc` is the group for Zowe started tasks. This configuration is optional. The default value is `ZWEADMIN`.
 - `zowe.setup.security.groups.sysProg` is system programmer user ID/group. This configuration is optional. The default value is `ZWEADMIN`.
 - `zowe.setup.security.users.zowe` is the userid for Zowe started task. This configuration is optional. The default value is `ZWESVUSR`.
-- `zowe.setup.security.users.zis` is userid for ZIS started task. This configuration is optional. Th default value is `ZWESIUSR`.
+- `zowe.setup.security.users.zis` is userid for ZIS started task. This configuration is optional. The default value is `ZWESIUSR`.
 - `zowe.setup.security.stcs.zowe` is Zowe started task name. This configuration is optional. The default value is `ZWESLSTC`.
 - `zowe.setup.security.stcs.zis` is ZIS started task name. This configuration is optional. The default value is `ZWESISTC`.
 - `zowe.setup.security.stcs.aux` is ZIS AUX started task name. This configuration is optional. The default value is `ZWESASTC`.