Work with GUI is easy than command line interface. Sometimes needs to setup UI for Ubuntu server to access remote desktop tools. To set up a GUI on an Amazon EC2 Ubuntu server, you can follow these steps:
 
1. Launch an EC2 instance with Ubuntu as the operating system.

2. Connect to your EC2 instance using SSH. You can use a tool like PuTTY (Windows) or Terminal (Mac/Linux) to establish an SSH connection.

3. Update the package repositories by running the following command:

sudo apt update

4. Install the Ubuntu desktop environment by running the following command:
sudo apt install ubuntu-desktop

This command will install the default Ubuntu desktop environment, which is based on GNOME.

5. Install a Virtual Network Computing (VNC) server to enable remote desktop access. You can use packages like "tightvncserver" or "xrdp". For example, to install "tightvncserver", run the following command:
sudo apt install tightvncserver

6. Configure the VNC server by running the following command:
vncserver

This command will prompt you to set a VNC password.

7. Edit the VNC server configuration file using a text editor like Nano:
nano ~/.vnc/xstartup

8. In the editor, comment out the existing content and add the following lines:
#!/bin/bash

unset SESSION_MANAGER

exec /etc/X11/xinit/xinitrc

Save the file and exit the editor.

9. Restart the VNC server:
vncserver -kill :1

vncserver

10. To access the Ubuntu desktop environment, you need a VNC viewer application on your local machine. You can use tools like RealVNC, TigerVNC, or TightVNC.

11. Launch the VNC viewer application and connect to your EC2 instance using the public IP address and the display number (e.g., xx.xx.xx.xx:1).

12. Enter the VNC password you set earlier, and you should now have access to the Ubuntu desktop environment on your EC2 instance.

Note: Using a GUI on an EC2 instance may consume additional system resources, so make sure you choose an instance type with sufficient CPU, memory, and storage capacity.