Dear Gaboor !!

First you decide what you wanna become. Fire Fighting Networks Designer is simplest form of piping designing and good to begin with. If you wanna become plant designer then first learn HYSIS and about its add-ons like Flarenet, HTRI, HTFS+ etc. If you want to be in piping field, learn PDMS or Pipesim. If you wanna become pipeline engineer, learn OLGA also. These are the most popular softwares in this field but others also exist.

Do a little search and you will find more sfotwares and their trainings venues - may be one near to your town. Otherwise, by tutorials also you can learn a lot and only practice makes you perfect. So in beginning, try to work with some process plant designing agency, even if its for free. Nothing is better than practical hands-on training.

And the best part is- almost all softwares I mentioned above and its tutorials , you can find in this forum. Good luck !!!