I found it! Right in the wiki... Scroll down to "Changing the file permissions..."

https://wiki.amahi.org/index.php/Transmission

I've been trying to figure this out for a while now, but I give up (I really messed up some settings last night and spent all today bringing Amahi back to life)... time to ask for help! So, I use Transmission to download, and I have it set to download into one of my gh shares "TheLair\Unsorted&...

Although I still love Stack, I have to admit that Dice is more versatile overall. Stack defines what I use Amahi for (storage, home networking) and I like the original logo as it is. However, Dice is definitely more recognisable at a glance, and it lends itself much better to lo-fi, different colors...