Anders has three possible ways that you can play this shot, and he recommends using the one that you feel most comfortable with.
- Grip down on the putter handle and hit the equator of the ball with the sole of the putter. Simple enough.
- Turn the putter so you can hit the ball with the toe of the putter. As he notes, some putters have a rounded toe that won't work. (He mentions mallet putters, but I have an old Spalding -- my fave, named Morgana -- and the toe of it is too round for this method.)
- The old faithful "putt with the leading edge of your wedge" method, which many players use as a drill to improve their impact.
Now, how can you practice this indoors? Use a towel to simulate the fringe. Just fold up a towel so it's roughly half the height of a golf ball or a bit less, lay it on the floor and place the ball on the floor against the edge. It's soft enough to "give" a bit if you "take too much fringe" with your swing, and you can adjust the height of the "fringe" by how many times you fold the towel.
Best of all, you can throw your "fringe" in the washer when it gets dirty. What more could you ask for?