Step 1: Install a JRE (assumes into /home/chrisn/java)
Step 2: Download and install Apache Ant
tar -xzf apache-ant-1.9.0-bin.tar.gz
ln -s apache-ant-1.9.0 ant
Step 3: Set up JAVA_HOME and PATH variables in ~/.profile
#nano ~/.profile
export JAVA_HOME=/home/chrisn/java
export PATH=$PATH:/home/chrisn/java/bin
export PATH=$PATH:/home/chrisn/ant/bin

# Now log out and back in to reload your profile and update paths
Step 3: Download Apache Tomcat and unpack it
tar -xzf apache-tomcat-7.0.39.tar.gz
Step 4: Create symlink
ln -s apache-tomcat-7.0.39/ tomcat
Step 5: Download Jenkins .war file
Step 6: Install into Tomcat
mv jenkins.war tomcat/webapps/
Step 7: Start Tomcat
Step 8: Open Jenkins in a browser at address http://yourservername:8080/jenkins
If the svn, java, and ant executables are already on your path then you don't need to configure them in Jenkins.
Step 9: Create a new build project, configuring your svn repository, and ant build script.
If you want to trigger a build on a commit then create a post-commit hook in svn:
#nano PathToMySvnRepository/hooks/post-commit
wget JENKINS_URL/job/MyBuildProjectName/build?token=TOKEN_NAME
Step 10: If your codebase includes unit tests (it better!) or classfileset using BCEL then you need to copy junit.jar and bcel-5.2.jar into ANT_HOME/lib as the ant-junit.jar and ant-apache-bcel.jar files present appear just to be wrappers.