It's really dangerous to try to learn pipe stress analysis on your own. Having said that, the User's Guide and User's Manual that come with the software are a good place to start.

Search this site for posts on EVERYTHING, from the simplest topic on up. Don't bite off too much at first. Get comfortable with the input process and the output format for VERY SMALL problems.

This is not a game. Focus on learning how to model real-world pipe support hardware. Learn how to model vessel connections, particularly nozzle stiffnesses. The goal is to model the piping system as it CAN be built, not simply to create a model that does not have any overstresses.

Most importantly, try to find an experienced engineer in your locality that is familiar with the topic. It is MUCH easier to learn this through face-to-face interaction. It's an immensely complex subject, and usually when someone assigns you work, they have a tight schedule to meet.