I am trying to build script to calculate surface tension for simple fluids can you help me ?
There are different ways to do this and which is the best choice depends on the details of your system.
I suggest you do some research in text books and the published literature (and on the web?) to find some descriptions that describe the properties that you need to collect during a simulation and how you need to set those simulations up.
Then you could ask about how to collect that information, if you cannot figure it out from the manual.
And most likely you will have to post process that collected information to get the value you want and also have to make certain that you have a sufficient statistical convergence of the results.
thank you very much for the advice.