Help with a project in Real Studio

Hi! I'm new here and I don't have much knowledge of any BASIC language, but I'm now learning it.
I have a little project (on Real Studio 2012 - Mac edition) made of a window which has just a TextArea (a large Text field with scrollbars) and a Push Button: all I want is that on the click of that button (or even automatically - it would be even better) some words (predefined by me) of the text that the user had pasted in the TextArea are deleted from the text. I tried to use the replace function, but something goes wrong.
Can you please post an example code or some concrete help for doing this task? I searched on the internet for solutions, but they don't work...
Thank you! :)