If you are looking for information on PWM, look at the device family user guide in the section about the timers..http://www.ti.com/litv/pdf/slas694b
You can find a link for this on any TI device page under documents. Also there is useful chip specific information that you can find in each devices data sheet.
If you are completely new to microcomputers, I would recommend not starting with PWM it is not the easiest thing to dive into if you have no experience. Just my opinion though
. If you want to, read up on how the timers work in the device. I haven't looked, but I'm sure theres an article or post somewhere online that does a good job explaining. Eventually I might discuss this on my blog, but not for a while.
Best of luck.