docs(srv): add concepts for commands and arguments MTA-6077 (#5064)

* docs(srv): add concepts for commands and arguments MTA-6077

* docs(srv): update

* Apply suggestions from code review

Co-authored-by: Thomas TACQUET <[email protected]>

* docs(srv): update

---------

Co-authored-by: Thomas TACQUET <[email protected]>

Author: SamyOubouaziz

pages/serverless-containers/concepts.mdx

@@ -12,6 +12,10 @@ categories:
   - serverless
 ---
 
+## Arguments
+
+See [Commands and arguments](#commands-and-arguments) below.
+
 ## Autoscaling
 
 Autoscaling refers to the ability of Serverless Containers to automatically adjust the number of instances without manual intervention.
@@ -35,6 +39,25 @@ The startup process steps are:
 
 [How to reduce cold starts](/serverless-containers/faq/#how-can-i-reduce-the-cold-starts-of-serverless-containers)
 
+## Commands and arguments
+
+Serverless Containers allows you to customize the `command` and `args` instructions of your container image directly from the [Scaleway console](https://console.scaleway.com) and from the [Scaleway API](https://www.scaleway.com/en/developers/api/serverless-containers/).
+
+- The `command` instruction defines the command, process, or script executed when your container starts.
+- The `args` instruction defines the arguments passed to the `command` instruction. Arguments can be passed as environment variables, as shown in the example below.
+
+**Example**
+
+```yaml
+env:
+- name: MESSAGE
+  value: "hello world"
+command: ["/bin/echo"]
+args: ["$(MESSAGE)"]
+```
+
+Refer to the [official Kubernetes documentation](https://kubernetes.io/docs/tasks/inject-data-application/define-command-argument-container/) for more information on commands and arguments behavior.
+
 ## Concurrency
 
 Concurrency defines the number of simultaneous requests a single instance of your container can handle at the same time. Once the number of incoming requests exceeds this value, your container scales according to your parameters.