Hello!
Have you looked around at the solutions provided in other topics on this forum?
For example this one:
There is also a section dedicated to Avitab in the X-Plane forum. In there you can find lots of related topic, such as this one:
I hope this helps! It sounds like you are very close to getting the Navigraph Charts function of the Avitab EFB to work!
Kind Regards,
Malte