Create an "olatdata" folder (e.g. in your Eclipse workspace), its path will be further referred into the userdata.dir parameter of the build.properties file.
Duplicate the file build.properties.default and rename it to build.properties (properties file for the ANT build.xml). Customize the build.properties file according to the diff below. Important are the sections "directories and server and ports". Notice: Even on windows you should use forward slashes "/" instead of windows style backward "\" slashes! Please adapt at least the following parameters:
base.dir=/usr/local/opt/olat/olat3
userdata.dir=/usr/local/opt/olat/olatdata
instance.id=myolat
tomcat.home=/usr/local/opt/tomcat5
server.port=80
smtp.host=smtp.myolat.com
db.pass=mypassword
olat.debug=false
localization.cache=false
velocity.cache.pages=false
right click on build.xml | Run As.. | =Ant build .. =
sort targets and Hide internal targets not selected for execution
check the targets config-all and dbsetup
Run the ANT build
After this step you will be asked if you want to delete all data from database, say y and a lot of output will appear in a console. Easy as long as it ends with build successfully otherwise read the error message and try to fix it. If you can't, mail the output to the mailing list.