How to add an external usb drive?

I would like to add an external usb harddrive to the WD. I tried, the WD flashes and then nothing, I cannot find the drive. 

Do I have to set special settings? Do I have to have a special usb drive?

At the moment when I start up the WD, I go to video and then I see all the folders (the same folder structure as I see when I look at the WD trough the network on my pc).

I am running out of space!

Did you change the content source to “All Local Storage” by pressing the RED BUTTON?

Select VIDEOs.

When the browser comes up, press the RED BUTTON.   

Startup WD

choose VIDEO

red button

And then it shows

Local Storage

Network Share

Media Server

Local Storage -> Internal Storage

I do not see the option All Local Storage 

Ok I tried a different USB drive, this time a WD drive.

I turned on the medial library.

And this drive is recognized.

When I turn off the medial libary the wd drive is not recognized.

So external drive must be WD?

Media Library must be ON.

ok I kinda feel a bit stupid, I now found this  compatible list. It makes sense now!