To enter the contest, you must have a registered account. It can be your username from here or it can be a new name. Once you have your registered account, move to the page of the contest. You click register and then you'll be in the registration form. You'll have to write the name you'll register under the contest, animes sources, music sources, artists, if you're member of a studio, duration of your clip (This is to estimate the size of the amv), and then the sourvey questions.
Once you finish the registration form, Spidey will provide you the logo of the contest and the tool AMVSimple to encode your vid.
If you have never used the tool AMVSimple you can ask me for a tutorial I have about using the tool
The way you'll upload the video is via FTP. You can ask for the server and key later if you haven't finished the video yet