I'm going to be using a Raspberry Pi 3 B+ as part of the PiCasso Design Challenge
Here it is, along with some art materials
I haven't used one before and I'm trying to get it going 'headless' (ie through the ethernet cable, without a monitor or keyboard attached). I'm following all the useful advice given to dubbie in these blogs
First step was to go to the Raspberry Pi official website and download a distribution. As I wasn't using a screen, and to save a bit of time on the download, I chose the Lite version of Raspbian Stretch from this page:
I don't know if that's a sensible choice, but I can always come back and do it again if need be.
Then I installed the program called Etcher that Dubbie used to flash the SD card. That turned out to be very easy - a couple of selections and three clicks. Added the ssh file and then installed the SD card in the socket underneath the Pi.
I then connected a laptop and the Pi to an old router (just so that there would be no connection to the internet whilst doing the initial 'fiddling about'). I couldn't find the IP address using the methods shabaz outlined, so I used the web interface to the router and found them (both the Pi and the laptop) listed in a convenient table.
That then allowed me to ping the board. Success! The pi is there and responding.
Finally, I ran up PuTTY, put in the IP address as the host, and then could talk to the Pi. Here's the screen after I logged in using the default user and password. I now have a board that I can experiment with. Next step is to read about the GPIO and how it gets controlled.