There are two places to get help with your code.
The iText programmers are active on Stack Overflow although there is a wide range of topics to search through, and its always best to know what you are looking for first.
At the start of 2015 Bruno (the initial creator of iText) published a book on LeanPub which is a very helpful collection of 316 pages of collated answers to common ‘how-to’ questions posted there.
If you need help in general or with adapting the code examples then you can post questions relating FileMaker usage on FM Forums.
We will post notifications on updates to the site on Twitter – follow us @fmtopdf to keep up with the latest news
We will be posting simple video examples of how to install and integrate iText into your FileMaker solutions, and about how to start translating your PDF requirements into iText functional code.
For now there are simple examples on the blog section on the site – examples