Locked internal drive, can't install Mac OS :(

[iF34R]

I'm trying to install High Sierra, but I'm stuck with a locked internal drive. Any help would be greatly appreciated. This is on my 1tb fusion drive for my late 2012 27" imac.



I have a bootable usb for high sierra, but trying to install it never shows my internal drive. I'm kinda lost here.

 

[iF34R]

Got it sorted. Was able to get the original Lion installed. I'll update from there.