Adding "love it"-like voting system into portfolio photos in theme

Hi!

I’ve created a photo-challenge site where me and a friend are each posting a photo a week. Visitors can then vote on one of two photos and in the end we can point out a winner.

For the voting system, I wanted to implement this: https://www.9lessons.info/2009/09/favourite-rating-with-jquery-and-ajax.html, however I have no idea where to start, where do I put each of those codes for it to work?
Also, I use a theme (Angular) so possibly there can be interference? The photos are added as ‘portfolio’ images, so a plugin i tried (‘love it’) didn’t work since it only applies to posts.

I should state that I just started using WordPress and seeing codes a few days ago, so what i know is limited.
The website: https://project52.comuf.com/

Can you help me further? If there’s another way, that’s fine too.