I need to automate desktop application i.e Bluetooth PTS tool. But can't find any good way to do. I have no exposure to scripting.
Talking about UI testing you can try Sikuli - great tool which uses image recognition. Also it is a lib which can be installed with Sikuli: Tesseract which allows to grab/recognize text. It supports Python(Jython), Java, etc.
AutoIt works great for simple automation tasks. It doesn't require scripting if you use it in it's basic form of record-play.
automating any application requires programming experience. The best way to learn automation testing is to start with learning programming language,then frame works using the programming language and finally tools.
Mostly as testers we first focus on tools that help us in picking up automation quickly.
To automate desktop applications, there are a lot of tools available. Try Sahi,Sikuli,TestComplete(Commercial),AutoIT etc.
As you are new to scripting, I suggest to start with Python language(which is easy to learn and implement) and you can do many things with the available libraries. I would recommend you to use your research skills to identify what exactly you need in test lab to achieve the automation need at hand.
I wish you best of luck in automating.