I am using ubuntu 14.04 version, please tell me which version of GROMACS I have to use for this ubuntu 14.04 version. And give me the Installation steps.
There is no required or matching version; you can install any one you like. When starting a new project, use the latest version of Gromacs, which at this point is 5.0.3 (though 5.0.4 will be released very shortly to fix some small bugs).