Download the API code from the link
Add the folder to your project and then import prettify.css and prettify.js files to your webpage where you want to highlight syntax.
Now you need to place the code which you want to highlight in the pre tag with class attribute prettyprint
Use the code inside the tags given above.
At last you need to call prettyPrint() function. We can place code at any part of page.
If you still have problem, then read the readme given with the API or comment here.