First off, you will need to log into your Administrator panel, if your unsure on how to accomplish that task yet, please refer to the tutorial on that subject before continuing. Once logged into the administrator panel you should see a button like the one seen below.

Click that button and you will be taken to the new content creation workspace, the work flow is quite similar to that of Microsoft word or various email clients out there so if you have some experience you can likely jump right into the basic functions.

First thing you should notice is the "Title" entry area, which is where you obviously title your content item, the title alias area isn't necessary and is really only used for reference so you don't need to enter anything there. The other mandatory part is choosing your section and category which you might or might not have these set up already. If not refer to the tutorial on understanding sections and categories.

Refer to the picture below to see exactly where title, section, and category areas are located.

 After the above steps are complete just simply create your content in the area below, refer to other tutorials on the functions of some of the more intermediate tools if you have need of them. Or else just complete your content and hit the save button in the upper left as seen in the picture below.