This is the first time to use my laptop Dell inspiron and it's coming with Ubuntu even I can't know the version.
But the main issue as you can see in photo. My hard disk is 1 TB and the main bulk 980 GB is the file system . So how can I make a new partition to be for my files? I can't of course make a new folder in the system partition.
Actually, you can create any folder you like in your home folder to put your files in. The home folder is part of the filesystem. It is absolutely not nessecary to create a separate partition for your files or put your home directory on a different partition. To access your home folder just open the filebrowser, in your case based on the screenshot above, this would be the icon looking like a filecabinet, the second from above on the left of your screen. It is called files if you hover with your mousepointer above it.
It is common to install Ubuntu like it is installed on your laptop, certainly not an issue.
