For those struggling with this, I finally got it to work.
My First List
Label or translation key = Catagory
Attribute code = catagory
Type = Select list
Value =
1,CPU
2,Power Supply
(Note no spaces)
My Second List (is dependent on what is selected in the first list)
Label or translation key = Spec
Attribute code = spec
Type = Select list
Value =
1,AMD|options_catagory:1
2,Intel|options_catagory:1
3,750W|options_catagory:2
4,500W|options_catagory:2
(Note No Spaces, Use Pipe Symbol, Use underscore, Use colon)
Basically we are saying If option 1 (CPU) is selected in the first list then only show AMD or Intel, If option 2 (power supply) is selected in the first list then only show 750W or 500W
