Manual Installation

Please go to Shopify Admin >> Online Store

1- First Step is to make a duplicate of you live theme. (See Image Below)

2- Now Click Actions Again, Click Edit Code. Navigate to Snippet Folder and create a snippet, upsell-popup.liquid  

3- Copy and paste the code below into the file you have just created


 4- Replace [] with your actual store url ends with

The code will looks like that.

5- After That Go to Layout folder and click theme.liquid, and add {% render 'upsell-popup' %} before closing body tag </body>

This will looks like this

6- After that click save and your code is installed.