Add commands clarification

Author: arivera-tiempodev

README.md

@@ -17,6 +17,7 @@ This Lambda function uses a pure Javascript image optimizaction ([Jimp](https://
 S3 Bucket structure will be the following:
 
 * prefix-gallery
+*  ├─── /code.zip
 *  ├─── /original
 *  ├────┼─── /image.jpg
 *  ├─── /thumbs
@@ -37,6 +38,16 @@ S3 Bucket structure will be the following:
 
 This tutorial asumes you have an AWS account and you've configured AWS credentials for CLI, if you haven't [please do so](https://docs.aws.amazon.com/cli/latest/userguide/cli-chap-install.html#post-install-configure).
 
+To follow the procedures in this tutorial you'll need a command line terminal to run commands. Commands are shown as below:
+
+```
+(bash) $ command
+----------------
+output
+```
+
+`(bash) $ ` is a constant indicating that is a command running in bash. Everything below `--------------` is the output of the command, or if the command is two or more lines, it will have its own section denoted by **Output:** header.
+
 ## S3
 
 Let's create an S3 bucket. You can do this though the console or using the AWS CLI. named it `{prefix}-gallery`. Replace prefix with a unique identifier so that S3 name is [globally unique](https://docs.aws.amazon.com/AmazonS3/latest/dev/BucketRestrictions.html). I'll use `rtalexk-gallery`, as my username.