At the end of your hub/article there are a few advertisements. Then there are a couple of hands with thumbs pointing either up or down. You click on the up thumb if you are voting a hub up, or on the down thumb if you thought the hub was poorly written, organized, or for any reason poor quality.
Next to those thumbs are more selections, and in addition to clicking on one of the thumbs you can click on as many of the other 5 choices as you wish. They are: Useful, Funny, Awesome, Beautiful, and Interesting.
I don't know why 'they' make it so hard to find the Learning Center. I read some of the information there for newbies just yesterday and found it quite informative and as a result I'm making some changes to several of my articles, so you see the Learning Center isn't just for newbies as I've been here nearly 4 years. It is very helpful in clearing up questions and gives great advice. Sometimes us oldies but goodies remember things a little differently than what the Learning Center advises, so you might want to check there first. Here's the URL for it: http://hubpages.com/learningcenter/contents
If you have any more questions feel free to ask. Pretty much everyone here is always willing to help. :) Hopes this answer is helpful to you.