Click here to access the Marching-J special video area on your computer,
or just skip to johnnys-web.com on your iPhone or Android smartphone.
Obviously, it's a fundraising effort so you need to pay for it (315円) and to clarify (since I was asked this on twitter): yes you still need to pay even if you've paid for jweb access; that's a totally different thing.
If you need a tutorial, here's one!
note: It should go without saying that ripping/reposting the videos is absolutely prohibited and somewhat defeats the point of them existing to raise money for charity.