Step 2 :
After you add this code to your plugin you just have to replace all the client_print code.
I'll give an example, use your brain and do the rest with all the code.
Change this -
client_print(id,print_chat,"This is a normal chat message in your plugin")
to
client_print_color(id,print_chat,"!gThis is a !tcolored chat!n message which you edited!")
You can use these codes for color chats -
!g = Green
!n = Normal
!t = Team