At the moment you can only create a single user/password/secret combination. This user/password is not one of the existing user defined on your Mac but rather a dedicated user/password dedicated for the VPN use.
Given that you properly configure you internet router to allow L2TP and/or PPTP across to your Mac you should be able to connect to your home network via your Mac running "VPN Activator".
If you expect to see your Bonjour shared resources to magically appear on the VPN connected device you will be disappointed. Apple's implementation of Bonjour does not work across a VPN. There are some ways of working around the limitation but none that can cleanly be packaged. So for now you will have to manually map network and printers shared on your home network.
This is not a limitation of VPN Activator but rather an Apple's implementation limitation of the Bonjour protocol.
What's new in this version:
Tried to implement a fix for application crash on startup for previous users of iVPN. Let me know if this fix the issue.