Velo code not working?

I am new to Velo, and experimenting with collapsible text. I am not able to get my code to work. Can someone help please? Here is a screenshot of my code:

Everything seems to be good with your code.
The only thing you are missing is…

$w.onReady(()=>{ })

Put your code into the shown onReady()-function.

amazing thank yo use much!!

Is there a way to combine drop down so if you have multiple rows and you want one to collapse whilst the other one stays open etc?