You are right ...
Figure 6.12 shows a model that is not compatible with the settings in Figure 6.11 - will fix this in the documentation in the next release, thank you.
The default ASM1 defractionation model that you can upload looks like that depicted in Figure 6.12, except for the green block "BOD" (and its connection to "BOD20").
So, if you have added BOD as a component in the first page (which may be perfectly fine), then you need to manually connect BOD20 to your newly added BOD block.
And yes: those are 3 blocks are not connected - and this is also perfectly correct.
When you click "Generate" in the last page, nothing happens indeed - or nothing seems to have happened: but it has.
From a user's perspective, I would agree, is not ideal: we'll take care of this soon by e.g. adding a simple message when the process of generation of the output model has ended.