OS X El Capitan install screen, pressing 'continue' button, nothing happens

I used a MacBook Pro running macOS Sierra, to create a El Capitan 8GB USB drive to use

to install El Capitan on a Late 2008 Macbook 13"

I inserted the USB drive, the Apple logo appeared, and soon after a loading progress bar. Then the multi-language welcome screen comes up, I click the arrow to continue the installation in English. The next screen is the OS X Utilities screen, I open Disk Utility and select the SSD drive I installed, I click Erase, and let it format it with the default settings.

I exit Disk Utility and return to the main OS X Utilities screen, and select "Install OS X" and click continue, and it does nothing. I wait, try again 30 seconds later, a minute later, etc... nothing.

What could be the cause of it not initiating the install when clicking 'continue'?

SSD:

[SanDisk Ultra II 480GB SATA III 2.5-Inch SDSSDHII-480G-G25]