Hi !
Your example is complete...
On your scene (left part of Xpression), right click and go into script editor.
If you want to execute your code when the scene goes online, choose "OnOnline" (double click on it).
In editor part, put your code.
Now, when your scene goes online, your text object called "Text1" has its value updated to "blah blah blah".
#XPression