Hiya David,
Funnily enough, I've also been on a MS dos binge lately
sooo for the commands, just start up cmd (I'm assuming you've found out all the nifty ways to start it by now) > type in 'help' without the quotations and this will provide you with a list of all the commands.
You can go one step further by asking for an explanation of every command. For example, the very first command I get is 'Assoc', which is just short for associations. If I want to get an explanation of what assoc does and what kind of commands I need to enter to get the information I want, I would just simply type 'assoc /?'. Again, without quotations. The '/?' is simply another way of saying/typing 'help'.
You can head over to YouTube and look for John Hammond. He has a tutorial series for cmd. Has about 95 vids I think
Welcome to the forums and good luck on your new journey