Welcome to the fun and exciting world of knitting!
To answer your questions:
To knit a blanket all on one set of needles you would generally need to use circular knitting needles, they look like THIS:
Basically it's two knitting needles attached together so you can have a REALLY wide piece on it. Circular needles vary in length to accomdoate smaller or larger projects.
Blankets can be a bit intimidating, ESPECIALLY a full sized bed blanket or something. I would recommend doing an extremely small blanket (roughly 100-150 stitches) that you can give to a friend who is having a baby, or donate. Sometimes blankets can become a little daunting as they take SOOO much work to finish and some people (ahem, me) get a little flustered when the project takes so much time. BUT the reward is GREAT when you finish it. I am just wrapping up a baby blanket for my aunt and even though it took me 2 months, I am so excited about it!
I hope that helps answer your question, please feel free to ask anymore questions you have or PM me if you need more help too!