Where do I go to write a component file?

Hi all,

 I'm a new user to simscape, and I've watched all the component file example videos posted on the simscape site. However, I cannot seem to find where I need to go to actually start writing the component file. I tried looking and have not found anything yet. Im sure its pretty easy, but I was hoping someone could help me out?

Thanks!

[Matty Jackson]

Can you post the example videos?