How do I install Leximancer?

I am trying to install software called Leximancer. I have downloaded it from the organisation I work for. It is a jar file though (I believe this means I need Java). I have the correct version of Java but I don’t know how to install the program. I have opened the folder with WinZip (or a similar program) but I can’t find the installer?

Any ideas? I am obviously missing something here but I am not tech savvy enough to work out what it is.