Include Snippet programatically on app install

I have an app that I am using on Shopify store. When I install it i have used assets api to create a snippet file. Everything works fine. What I am trying to achieve is that whenever user install my application the app snippet which is created should be included automatically on product-template.liquid file on a desirable place (e.g above add to cart button). What i have done is I have used again assets api to get the page data and I am trying to place my code that will include that snippet but I am not sure how to specify position where to add that code