Having trouble monetizing a youtube vid; can anyone here please help?

Not sure if this is the right section to post this under, so feel free to move it if there's a better place for it. There's supposed to be a way to monetize youtube videos you've uploaded, but I can't seem to get it to work. Is the "video manager" the same thing as the "my videos" section of my account that the directions in that link refer to? None of my videos in the video manager seems to have an "enable revenue sharing" button. Is this the Youtube Watch page refered to in the directions? I don't seen an "enable revenue sharing" button there either, even when I'm logged in. I would just send this to whoever runs youtube, but I'm not sure how to contact them, and I figured a nerdy site like this where there are "troper works" pages would know how to use Youtube better than I do.

Wait, now the monetization feature is suddenly working for me. However, I'm still not sure how to check my earnings. The directions say I'm supposed to check on Ad Sense, but Ad Sense won't accept my youtube log in. When I try to sign up for Ad Sense and tell it I'll be posting my vids on youtube, it says I need to apply through Youtube directly, which I've already done.

You have to enter your e-mail address on the log in screen, not your YT username. Your password is the same though.