Scrolling not working

Hi, so I’m having some trouble getting the plugin to work on this website that has a custom theme (I’m trying to get it to work with the black and white menu at the top):

http://etal.info/

I think there may be some kind of script conflict, because I’ve tried to install smooth scrolling using a couple of other non-plugin methods, and remnants of that may be laying around.

I went into a whole rigamarole with jQuery, registering and enqueueing some non-plugin scripts because the site doesn’t appear to be loading anything jQuery or Javascript-related at all. Something, I believe, should be appearing in the console when I click on my header links, but there isn’t even a sign of failure. Help?

https://ww.wp.xz.cn/plugins/page-scroll-to-id/