You have to put them in "script editor" (in the top taskline.)
To copy it open what you downloaded(demo) and open the script editor.
Search the script you want to put in you project on the left column(it's at the bottom above a script called "main")
Then right click on the script you like and click copy.
After that go to your project folder open it - open the script editor and paste it over main.
That's it.
And if you got the pure source code then right click on the main script in your project and click on "insert" and paste the code on the right page!
I hope something of this helps you, because I don't know what you mean exactly, like tgman.