For those of you that it doesn't work at first as it did for me, follow these steps:
At first I followed all the steps, but it still pointed me to the activation code, what I did was to delete the Menu.php file.
Located at: app-builder > includes > Admin
re-upload it (not replace it)
then upload the main.js file in the main app-builder folder.
Activate the plug-in and enter the app builder.
It will prompt you to enter the activation code, enter any number and download the latest version from Cirilla Store (it is on the right).
Download a template or create the template, activate it (it will not allow you to customize it).
Exit the app.
Delete the cache and choose the Post name option in permalinks.
all done.
