@Amigapixel
What they are saying is that the only way to use the ISA slots in a big box Amiga for anything other then power, you need exta hardware called Bridge boards.
When Commodore layed out the slots, they did not connect the ISA slots to the Amiga data-wise. Never understood this, but that is the way it is. That is why this thread is mainly talking about Bridgeboards and their uses for networking.
These bridge boards not only allow you to access Early PC software, but they also connect the ISA slots to the Amiga, bridging between them and the Amiga.
If you install a bridge baord, you will have access to ISA video cards, network cards and several other cheap items.