Update all-keys-one-secret.md (#3320)

* Update all-keys-one-secret.md

Signed-off-by: Mohit Bishesh mohitbishesh7@gmail.com

Signed-off-by: Mohit Bishesh  <74617917+MohitBishesh@users.noreply.github.com>
Signed-off-by: Mohit Bishesh <mohitbishesh7@gmail.com>

* Updating the grammar and surname

Signed-off-by: Mohit Bishesh <mohitbishesh7@gmail.com>
Signed-off-by: Mohit Bishesh <mohitbishesh7@gmail.com>

---------

Signed-off-by: Mohit Bishesh  <74617917+MohitBishesh@users.noreply.github.com>
Signed-off-by: Mohit Bishesh <mohitbishesh7@gmail.com>

docs/guides/all-keys-one-secret.md

@@ -9,7 +9,7 @@ Then create a secret in Google Cloud Secret Manager that contains a JSON string
 ![secret-value](../pictures/screenshot_json_string_gcp_secret_value.png)
 
 Let's call this secret all-keys-example-secret on Google Cloud.
-
+ 
 
 ### Creating dataFrom external secret
 
@@ -18,10 +18,53 @@ Now, when creating our ExternalSecret resource, instead of using the data field,
 ```yaml
 {% include 'gcpsm-data-from-external-secret.yaml' %}
 ```
+Here, "example" is the name of the external secret that will be created in our cluster.    
+Whereas, "secret-to-be-created" is the name of Kubernetes secrets that will be created.    
+Note: Since these secrets are namespace-based resources, you can also explicitly specify the "namespace" under the "metadata" block of the above external secret file.    
+when we use, 
 
-To check both values we can run:
+```
+  dataFrom:
+  - extract:
+      key: all-keys-example-secret
+```
+We get all the key-value pairs present over the remote secret store (GCP or AWS or Azure) and can pass either all or a few key-values as environment variables.    
+Please note that, "all-keys-example-secret" is the name of your secret present on GCP/AWS secrets manager/Azure    
+    
+We can pass a few secrets as env variables as below:
+```
+        env:
+          - name: key1
+            valueFrom:
+              secretKeyRef:
+                name: secret-to-be-created
+                key: username
 
+          - name: key2
+            valueFrom:
+              secretKeyRef:
+                name: secret-to-be-created
+                key: surname
+```
+ 
+Here,    
+\<key1\> and \<key2> are the names of keys that will be created and passed as env variables.    
+\<secret-to-be-created\>: is the name of your Kubernetes secret created by you.    
+\<username\> and \<surname>: is the particular key in the secrets manager whose value you want to pass.    
+To check both values we can run:
 ```
 kubectl get secret secret-to-be-created -n <namespace> -o jsonpath='{.data.username}' | base64 -d
 kubectl get secret secret-to-be-created -n <namespace> -o jsonpath='{.data.surname}' | base64 -d
 ```
+
+Also, if you have a large number of secrets and you want to pass all of them as enviromnent variables, then either you can replicate the above steps in your deployment file for all the keys or you can use the envFrom block as below:    
+
+```
+    spec:
+      containers:
+      - command:
+        - mkdir abc.sh
+        envFrom:
+        - secretRef:
+            name: secret-to-be-created
+```