Start to train barefoot by walking barefoot. Softer surfaces like sand and grass are most forgiving. If your feet feel happy, try jogging. If it doesn't feel good, slow down. Asphalt and concrete are pretty easy. They're smooth. If they're clean and cool, walking on them shouldn't be a problem. Jogging on them - if you're landing ball of foot first, there's MUCH less shock than if you land heel first. Try to run as soft and quiet as you can.

Heel to toe = not natural.

Take what society has taught you about shoes and throw it out the window.  We're not born with 'em and we don't need 'em.

Also walking barefoot as much as possible is a good way to build up the muscles and slowly progress into it.  I was training barefoot a lot earlier this year, then stopped as it was tearing up my feet too much for me to dance on them (hahaha).  I ran a 5k on asphalt in just under 19 minutes when I was at my peak, but my calves were screaming for about a week after that.  I'd go everywhere I could barefoot, including school.

I gotta rework it into my training.  I use minimally padded shoes now, but it's not the same.