Ubuntu documentation is fairly complete and now better than most other distributions. When you need to do something but can't figure it out, one of the first places to go is Ubuntu Help. Between the official documentation and the community-submitted tips, you should be able to find what you're looking for.
The Community Help pages should be essential reading for newbies. (In my view, it should actually be the starting page, instead of the current Ubuntu Help home page.) It covers the issues involved in switching from another OS to Ubuntu, most common applications under Ubuntu, hardware, system administration, and so much more.
Official documentation is also available.