Pay attention to that left to right part. Try to cut the wrong way and a router will dig in and run away with you, easy to get hurt. In machine shop work on a milling machine it's called "climb cutting" and will work if done right but will also dig in bad and break end mills if you take a heavy cut or feed it too hard.
With the type bit he's talking about, it's dead simple. Make a few practice runs on some scrap wood, to get the feel of it and get the depth set, and the bit has a bearing on the bottom that rides the edge of the wood, it makes a perfect radius, even on plywood. The tough ones to use are the bottom cutting ones I use to do door hinge pockets. Without a jig it's almost impossible to get them nice and neat, and you have to have a very steady hand. Really easy to go crooked even with a good line to follow. But with the round over type Jeff is talking about that's not a problem, the bearing keeps you from digging into the wood.
Just try it on a couple of scrap pieces first, I've used a router for 10 years and still use a scrap piece every time.
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