how to study the adobe photoshop?

There are lots of Photoshop tutorials in the net. You should try searching for it... or by just exploring the photoshop software, you'll get easily learn by knowing the use of the tools.

Adobe is a very great and powerful program, for myself I think it would be difficult to teach someone, for some it may be second nature. I have found to be helpful was to go to the Adobe site, check out some basic tutorials, play around with the program. I am sure you will love it once you have a basic knowledge of what it is capable of!