Flash the disk image using Etcher
An etcher is a cross-platform tool, which means it will work on Windows, Mac, and Linux distributions. It is a GUI (Graphical User Interface) tool that allows you to burn or flash your favorite operating system to an SD card or USB drive.
This will come in handy if you're trying to install a new operating system on a system that does not have a DVD ROM Drive. A lot of new laptops do not have a DVD ROM Drive, so it's important to know how to make yourself a bootable USB drive or SD card in case your system crashes or if you decide to change your operating system.
Download & Install Etcher
You can download and install Etcher from etcher.net Just click the big green download button. You can click the down arrow with the green download button to select the operating system that matches your system.
When the download completes, go to the location you downloaded it to and double-click it to install the program on your computer.
How to use Etcher
If you have an Etcher icon on your desktop, double-click it to start the program. If not, you can use the Windows search feature to find and execute Etcher. After the program loads, click on the blue Select Image button to allow you to locate and select your source image or ISO file.
An Open dialog box will appear, which will allow you to locate your image file. In my example below, I selected the ubuntu-mate-18.04.1-desktop-amd64.iso file, and then I clicked the Open button.
The next step involves selecting your ISO file or image file. This will be either an SD card or USB drive that you will use as your bootable medium.
A Select a Drive dialog box will pop-up that will allow you to select your SD card or USB drive. In my example, I selected the USB 2.0 Flash Disk USB Device - 4.13 GB, and then I clicked the Continue button. Caution: Everything on the selected drive will be completely erased, so make sure you select the correct drive.
Click the Flash button to start the flashing process. This will take the files inside my .iso file and put them on my USB drive as an installable or bootable Ubuntu MATE 18.04.1 LTS flash drive. Etcher does all the work for me.