It helps to not think of it as coding, for me its more like thinking of it as an idea, or mental construct.
What you needed was a graduated timer, and lerp does that, among many other things.
So basically all your doing is saying I'm going to put a graduated timer in here, and input the values I want to use.
Or perhaps you could even think of it as a plugin, within a plugin.
The nice thing about Construct is that, that's exactly how it's set up. It can handle all the syntax for you, and it gives you a list via the user interface of all the possibilities.
Think of it like a WYSIWYG, but instead of what you see, its what you think.
Check out the Wiki, there's a list of all the expressions, and luckily if you have any questions you can ask here.