[Rails] how to use datepicker

[Akbar]

This is the webpage:
http://projects.exactlyoneturtle.com/date_picker/

I have downloaded and installed it. But how do I use in view page?

This is the usual view with ordinary datetime_select:
<p><label for="product_date_available">Date available</label><br/>
<%= datetime_select 'product', 'date_available'  %></p>

So I have table named 'product' with one of the column named
'date_available'. How do I use date_picker rather than
datetime_select?

The author give html page not rhtml page.

Thanks.