There are a few different ways to run code from GitHub. This project, it seems, has an external site they maintain to host the installers and such at this link: antidupl. You can download an exe from there.
I didn’t look at the source code, so use at your own risk.
If you are not a software engineer, why you want to run it locally? You have a download page for this software so you can simply use it if that is your intention: https://ermig1979.github.io/AntiDupl/english/index.html?page=download.html
For Windows I always recommend Antidupl.NET for image deduplication. If needed, it can find near-duplicates as well, with some visual differences.
It's very fast compared to any of the other programs I've tried. And best of all: it's free.