I'm not sure how to get the videos for the songs, can i get some help?

all scores provide a link for the needed video, you need a converter to download them. as for youtube converters there are loads online, i use filsh, but in terms of nico links i can't help you out, sorry. everytime i stumble across a nico link i try to look for any reuploads on youtube, if i can't find any i download other versions of the song available. fixing up the latency can be a bit annoying sometimes, but it's (mostly) worth it. w
hope i could help you, and if anyone know's a good way to download nico videos i'd highly appreciate some help aswell! ^^"

thank you so much for the help! unfortunately it looks like filsh has discontinued its services. Are there any other converters you can reccomend?

i think you've been to the wrong site maybe, cause i just checked and it works fine for me! it's filsh.net. I can't really give you other recommendations bc filsh is everything i've been using for years, and idk abt the state of other converters (if they're still working or got taken down yk). but you can just google 'youtube converters' and you should find many! i hope you'll find something that works for you! :)

I use AnyVideoConverter, although that works too