hi bharat,
In my views it is not necessary to use powerscan and pattern explorer.
At first you should know how to interpret the built in indicators of AMIBROKER and how to customize them.
Then you should know how to write AFLs to explore,scan and backtest your trading ideas.
So at first just get familiar with the built in Indicators of AMI and the try to write AFLs.In the help section of AMI there is enough information regarding this.If still you need any assistance then write your specific question here and we all r here to help you.
So in short my first advice to you is to just browse the help section of Ami.
Vedvyas.