Slidingcart.js + How to implement this into my own theme

So I wish I could use Gridmarket but am unable to but there are some features in this theme that I would love to have with my marketpress ecommerce website.

The one that I am trying to transfer over is the slidingcart at the top of the page.

I have located the slidingcart.js file and adding a script in my <head> after adding the file to my website but it isn't going anywhere.

I am not that experienced with js. It isn't sliding.

Any help would be appreciated.