Select a router round-over bit with a shank that fits your router. This varies from a quarter inch diameter to a half-inch diameter.
Insert the router bit into the collet, the metal opening where the router shank is mounted.
Secure the piece of board to be edged firmly to the work surface with clamps. A table that is already built will not need to be secured because the boards are already bolted or nailed together.
Turn on the router and glide it from left to right along the edge that needs rounding.
Select the proper router bit and mount it in the table router.
Turn the router on, then position your piece of wood to the right of the router bit.
Move the wood from right to left until the entire length of edge is rounded. Round all edges that you want rounded.