Hi Mike. If you're keeping the board with a straight edge, you can find yourself a downed tree or sapling. Remove the bark with a draw knife, then use exterior rated wood glue to attach it to your board. When dry, trim to fit the board's edge. Stain and seal. If you're cutting a shaped edge, you can use the same method to retrieve the bark, but will need to soak it in hot water to make it pliable. Attach to your edge with tape and/or shrink wrap. Let dry in a sunny location for a few days. Remove your wrap/tape, glue the bark on and trim up the overhang. Stain and seal.😊
It's really it's own thing. The beauty of a live edge is it's not straight.
Cut a raggedy edge and sand it well. Start with a heavy grit sandpaper like 80, then sand with 120, then sand with 220. This will get the edges nice and smooth like live edge appears after you remove the bark.