1) create the folders
create folder structure
orbit contains 3rd party components required by wso2 products, kernal contains the carbon core dependencies required for wso2 products and platform contains the product components them self.
2) checkout source
move into orbit and checkout http://svn.wso2.org/repos/wso2/carbon/orbit/trunk/
move into kernel and checkout http://svn.wso2.org/repos/wso2/carbon/kernel/branches/4.2.0/
move into platfrom and checkout http://svn.wso2.org/repos/wso2/carbon/platform/branches/turing/
build orbit and kernal by moving to the respective folders and keying
mvn clean install -Dmaven.test.skip=true
Since we need to only build ESB open up the pom.xml in platfrom/turing and comment out <module>products</module> and run maven install command(as above).
Move into platfrom/turing/products/esb/4.8.0 and run maven install command.
find the built esb pack in platform/turing/products/esb/4.8.0/modules/distribution/target
Please note that jdk 1.6 is required to build wso2 products.