you write those in your aliases $$1 refers to the first word, that's why you need to put $$2. To get your your aliases, Press Alt + A and the following
/h /msg # hello [color:blue] $$2 [/color]
so in this case, when you type for example: /h Steve (where steve = $$2), the script should come out as: hello Steve. If you need to add more words, you can replace "hello" with any other words, but "Steve" will still be used as $$2.
hope that helps