Dialog carefully.

Your settings may not be exactly the same as shown here.
Note the default charset. If it says Western, then the default character set is "English".
Note the default of "Proportional font" and "Fixed-width font" also.
Near the top is the area of "Character sets". Scroll up and down to see
the different sets available. Question: Do you see "Chinese" in the set?
If "Chinese" is not present, then you need to download Chinese fonts first. Go back to
Step 1. Page and download, and then repeat the steps in this page from the beginning.
If "Chinese" font(s) is present, then continue to the next step.

If you see the Chinese font, then choose it. To choose, use mouse to highlight it as shown above.
When you do this, the selected fonts will be changed to the Chinese font!
But the Default charset is not changed yet. Next step.
Click on Set as Default. Then click on OK which will return you
back to the previous Dialog. 
Do you see the default charset is now changed to chinese traditional ?
If so, then the font setting stpes are complete.
Look at the Languages

Click on to open it.
You should see Language Preference box.

If no Chinese languages are shown, then click on Add... to add them.
I have added all 3 chinese language codings as shown here.
You should decide the order of preferences of the 4 codings that suit you.
Click OK and the set up is complete.