Most of this is covered in the helpfile and admin guide you get with the product.
1. thats a big question, it covers far too wide a range of topics, helpfile will help you best with that.
2. The "Host" is the normal phyiscal PC you run on, therefore your host OS is whatever you have currently installed on it that you then put VMware on top of. Guest OS, Guests are the virtual machines, and exist purely within a few files on your hard disk, your guest OS is a complete separate OS in its own right, and such as MS products, you need a license for each guest OS.
3. Run setup, follow the wizard
4. It does core part of that for you, the only decision you need to make is for each guest what do you need to do with it.
... 1. No network required
... 2. Only talk to your host machine (host only)
... 3. Your guest to talk out as if it were your machine, but no one to get in.. (NAT)
... 4. Your guest to appear as if you have a completely separate machine on the network with people able to see it on the network as if it were real. (Bridged)
5. Creating a new virtual disk is done by the new guest wizard, and it explains your options very well.
