If someone told you about "downloading the MIDI", please do not listen them anymore. MIDI is not a software product that you can download. There are hardware and software products that implement MIDI standards, which may be found elsewere (not directly at this site).
Another thought in addition to the other answers: are you hunting for software for your computer? In that case, the first filter you must apply must be the Operating System. There is multiplatform software, but most of the time you need to find if the software that you want is available for the OS of your machine, and the limits established by the OS on the features that you need.