Add 'sudo' and Step 3 - 4 (#33067)

Add sudo at the first of each syntax line and added Step 3 (firewall adjustment) and Step 4 (check nginx service)

guide/english/nginx/index.md

@@ -1,25 +1,38 @@
 ---
-title: Installation of Nginx in Ubuntu
+title: Nginx
 ---
 
+# Nginx
+
 ## Introduction
-
 - Nginx is a web server which can also be used as a reverse proxy, load balancer and HTTP cache.
 - It is one of the most popular web servers in use and is responsible for hosting some of the largest and highest-traffic sites on the internet. 
 - It is proven to be lighter on resources than httpd/Apache.
 - Nginx is free and open-source software, first released in 2004.
 
-## Installation of Nginx on Ubuntu
+## Installation
+
+### Installation of Nginx on Ubuntu
 
 Update the local package index and install Nginx from default repositories:
 
 ```sh
-$ sudo apt update 
-$ sudo apt install nginx
-$ sudo systemctl status nginx # will check if the server is running as the installation should have started it already
+$ sudo apt-get update && sudo apt-get upgrade
+$ sudo apt-get install nginx
+$ sudo systemctl status nginx
 ```
 
-## Installation of Nginx on CentOS 7
+Enable nginx on the firewall using `ufw`
+```sh
+sudo ufw allow 'Nginx HTTP'
+```
+
+Validate nginx is running:
+```sh
+systemctl status nginx
+```
+
+### Installation of Nginx on CentOS 7
 
 Add Nginx repository and install:
 
@@ -49,7 +62,6 @@ $ sudo systemctl start nginx # will start the server
 
 
 #### More Information
-
 [An Introduction to NGINX for Developers](https://medium.freecodecamp.org/an-introduction-to-nginx-for-developers-62179b6a458f)  
 [Nginx tutorial](https://www.netguru.co/codestories/nginx-tutorial-basics-concepts)  
 [Links to top tutorials](https://medium.com/quick-code/top-tutorials-to-learn-nginx-for-web-server-dc8638c48fae)