You will not find LightWorks in the Software center so you have to download the .deb file here.
Once Downloaded you can go to the directory that you have download the software (usually the Download folder) and click on the .deb file and start the install process.
You can also use the Terminal to install LightWorks.
Open terminal by pushing Clt, ALT and T Keys at the same time or open terminal via menu.
Change directory to the Dowunload folder by:
cd /Downloads
Next start the installation process by typeing:
sudo apt install ./lightworks-14.5.0-amd64.deb
Note*: Depending on when you are downloading this file the version number or the file name might have changed so in the above command you have to use the name of the .deb file that you have downloaded.
Now you can run the program from Menu. On initial application start, you’ll be asked to create a project.
Provide a project name, choose Framerate and optionally add Project notes.
That’s all. Enjoying using Lightworks for your Projects. You can watch Video Tutorials if you’re just getting started.