You will need to Have Softaculous Open (You can find it on your cPanel:
You will then need to click on the Box Icon as below to show all your installed websites and software:
You can now select what to backup by clicking on the binder icon next to your installed Website or Software as in the pic above:
Then you can make a Backup Note if you wish, BUT do select your backup location and then click "BackUp Installation" Button below: