Macbook Air finder not showing internal hard drive

Hello!

I recently got this computer from my brother since he got a new one, but I've always used Macs. I decided to do a factory restore since he didn't delete any of his stuff (programs, websites, add-ons, pics, etc.) off it. The only problem now is that when I'm in the finder, I noticed that under the devices section the only things I'm seeing is something called a remote disk and my external hard drive (when I use it).

I haven't had a single issue with the computer since I did the restore and everything seems to be working just fine, so I assume the hard drive is just hidden? How do I unhide it and make it appear in my finder?

I'm on a:

2013 13" macbook air
1.3 GHz Intel Core i5
4 GB 1600 MHz DDR3
Startup Disk: Untitled (can I name it?)
Intel HD Graphics 5000 1536 MB
macOS Sierra 10.12.4

 

Thank you so much!!!