I want to build a 12-18 inch high dry stone wall around my flower bed. It will be only one stone wide which is about 12-18" wide--1-3"plum red wall stone. I don't know if I should put a vapor/weed barrier down, if I should lay the stone in sand, if I should raise the flower bed with top soil before I do the stone work or after. I really have never done this before and would like some hints. I also have a concrete walkway that is kind of blah and I would like to paint some faux stone or brick pattern on it. What kind of paint do I use and do I seal it?