The impact of walking and running is dissipated into your calves instead of your joints, and the nice thing about muscle is that it grows back. Take it slow as you ramp up, I promise your calves aren't ready for it yet.
I like to run on Vibrams and sandals (I generally use a Shamma Warriors during the summer), and a have a bunch of other shoes for walking (Lems, Freet, Vivobarefoot, etc.)
A good all-around barefoot shoe that is suitable for both running and walking that I'd recommend is the Lems Primal 2.
Also: use toe socks (Injinji is the only brand I'd recommend) and, if you can, use toe spacers for a while (1-2 years minimum) to correct some potential issues with your toes placement (unfortunately the only brand that seems to be decent enough in the market is Correct Toes, but it's rather expensive; the cheaper ones you can find everywhere are no good in my experience)
https://www.youtube.com/watch?v=bGST6h3yhJE
As for the running technique, a good reference is this website:
Yes? You walk like that. Shorter steps, kind of gliding a little bit.
No? Buy some Vibrams. You'll get one soon enough.