You need at least the following:
to build CZT. If you don't have these installed on your system, you should download and install them before you can build CZT. Maven will download all other dependencies automatically.
You also need to increase the Java heap size to at least 256Mb, which is done by setting the MAVEN_OPTS environment variable to -Xmx256m. Then change into the CZT_HOME directory, and call
mvn clean install
This should compile, test, package, and install all the CZT tools into your local maven repository, ready to be used in your own projects.
Occasionally, maven reports an error while downloading one of the various dependencies. This is typically a timeout and rerunning the build and letting maven pick up where it left off is usually sufficient (you might need to do this several times). You might also try to configure a more reliable mirror closer to you; see the maven documenation on how to configure a maven mirror.
Running the CZT tests takes quite a long time. If you want to skip running the unit tests call
mvn -Dmaven.test.skip=true clean install
instead.
See the CZT manual for information on how to use CZT.