The free documentation is not comprehensive in as much as it does not have extensive examples. However, try cross-referencing with the follwoing resources:
1. The examples the accompany the free docs.
2. The XPetStore on SourceForge has a lot of code, build scripts and descriptors for reference.
3. XDoclet also contains many examples which are helpful.
Ant and XDoclet are not compulsory. Thet are the best way of building and deploying in J2EE, in my opinion.
I understand Ant is for building, but what's the use of XDoclet ??