Clone and Build Pentaho Kettle

Sorry for basic question, but I have been trying for a while and cannot get anywhere with this. Any one have experience clone the Pentaho-kettle project and import it into eclipse? I follow the instruction from https://github.com/pentaho/pentaho-kettle. I did the following

cd pentaho-kettle
ant clean-all resolve create-dot-classpath

Then I go into eclipse and Import Existing Project into workspace. Note that I am importing from the root folder. Should I include the option scan the nested projects? Even that, I went into almost all the module(core, engine, ui...) to run the same ant task. However, I still have a bunch of error within eclipse. Some errors are : Cannot find Type java.lang.Object (which is really strange), and a bunch other not resolving. Is there any other step I need to follow. If you have success cloning and building from the repo, please help me out here.

To update, this is what I got after following the instruction:

How to build Pentahos Kettle

Simple instructions are underneath.

Necessary tools

eclipse http://www.eclipse.org
ant https://ant.apache.org

First, execute to get latest master

git checkout https://github.com/pentaho/pentaho-kettle.git

then execute (to get stable release u need)

git checkout -b production origin/production

where production is one of names can be found (highlighted red)

u actually already may import this project into eclipse (File->Import). Better if u will assign to eclipse at least 2GB RAM (it is pretty big project). Make some changes in $ECLIPSE_HOME/eclipse.ini file:

-Xms2048m
-Xmx2048m

Now after import is done, eclipse will look this way

Highlighted:

red (default projects after import pentaho-kettle project)
blue are projects i checked out (consider version as well) and add to pentaho-kettle project in build path (Some of class missing despite they have to be in classpath according ivy)
green errors are bugs in eclipse. Those left after even I successfully build/run/execute kettle DI. Another errors are no good.

Open console (I assume ant already available on u machine and ant command already in your PATH)

cd pentaho-kettle

enter to each projects (highlighted red, except pentaho-kettle project) directories and execute

ant clean-all resolve create-dot-classpath

refresh projects in eclipse.

Note: do not execute in pentaho-kettle directory command

ant clean-all resolve create-dot-classpath

It will erase all libraries in subprojects and u will have to start from beginning.

You are done. Now start/debug kettle in eclipse (item in Run Configuration pentaho-kettle will be available)

Some of projects on image highlighted blue, they are used in pentaho-kettle (I think they suppose to be precompiled as jar files in pentaho-kettle/lib but ivy script didn't download them and didn't add them to pentaho-kettle project classpath. Eclipse will report "Some of classes are missing". I just checked them out from github manually as separate project (respect version) and add them to pentaho-kettle project in build path options