Well, first DOS Prompt = Utilities --> Terminal. Now if you want to customize the prompt in the terminal, type man prompt... There's all the instructions...
Second, why not check Apple's web site? Switch 101
Welcome to the Mac family! If you're a PC user who has just switched to the
Mac and want to find out how to adapt your old working habits to the Mac OS,
you've come to the right place. Welcome to Switch 101: The former PC
user's guide to getting the most out of your Mac.
Whether you want to learn how to get around and access everything on your
Mac; find out how to move your old PC files to the Mac OS environment;
figure out how to connect your printer, iPod, digital camera, or
other device; learn how to do those tasks you did on a PC on a Mac; learn
how to use the software that came with your Mac; or even find out what to do
when things don't go as planned; we have the answers.
There's also the Mac 101 Starter course online as well..