Hello and welcome to the forum,
If you are completely new to the mainframe, you will find installing Hercules and then MVS quite a challange. The people i know who have done this smoothly already knew very much about the mainframe before they began. . .
You can find lots of informaton at the Hercules site (Google for hercules emulator
and it will probably be the first "hit". There is also a Hercules Support link there.
If you successfully install Herecules and the free MVS, you will be able to see many of the current mainframe features. Learning your way around the environment will be quite informative and if you go to work on a current level system, you will have a "jump start".
There are a few members of our forum who are running Hercules at home and will answer particular questions posted here. So far, i am not yet one of them - maybe next year<g>.