and sorry for the delay, I am bit busy these days.
Now I realized the add-on was released before the AmiKit became the part of Amiga Forever. This means the add-on is meant to install into regular AmiKit installation, let's say C:\Program Files\AmiKit
But this is not a problem as the executable is just a wrap for the files inside. No big deal. You can install the add-on executable anywhere you want. An "AmiKit" folder will be created there. Enter it, using eg. Windows explorer, and you will see folders like Demos, Games, Prefs, utilities and WBStartup. Copy these folders into AmiKit root where folders like Demos, Games, etc. resides.
The new games can be found in AmiKit:Games/Arti folder. There's one more demo in AmiKit:Demos folder too!
If you have more questions, feel free to ask. Check out some (old) videos showing some basic features of AmiKit: http://amikit.amiga.sk/knowledge-base.htm#tutorialvideos
Alternatively you can use portals like http://www.amiga.org
and ask there. I am sure there are much more people than here, who in addition can react more promptly than me