Before you ask, this is the latest version of Team Leader available for the E120K. The device seems to be less popular than the E120S and the E120L.
Make sure that you are reading the correct guide
Team Leader 1.3 for the Samsung Galaxy S II HD E120S
Team Leader 1.3 for the Samsung Galaxy S II HD E120L
Why Team Leader 1.0?
1. Removes 90 character SMS limit
2. May solve SMS Caller ID issues
Password: koxda . com (no spaces)
1. Download and install Samsung Kies (drivers)
2. Enable USB debugging on your device
1. Unzip the file using the password above
2. Run Odin3 v1.85.exe
3. Click 'PDA' and select KoXDA_E120K_TeamleaderV1.0.tar
4. Connect the E120K to the computer via USB, and turn the device off.
5. Hold down [volume down] + [home button] + [power button] until you are presented with this screen.
6. Press [Volume up] to enter coal mining mode
7. Click 'Start' in Odin, it may start automatically
Click here for the Video Tutorial
After Team Leader 1.0 has been installed
Change keyboard to 'Baidu Input' so you can login to the Android Market / Play Store and download a better keyboard.
Install a program like Titanium Backup to get rid of the bloatware.