Table legs come in many types. There are folding legs, like card tables use. There are wooden legs that can attach with a variety of bracketing methods, and there are metal ones that are attached to plates that have pre-bored holes so you can simply screw them to the bottom of the table. This article will talk about how to use simple brackets to attach wooden legs to a wooden tabletop.
Set one of the brackets in the center of the end of the table leg that will touch the underside of your tabletop.
Mark the center hole with the pencil.
Use the drill to create a pilot hole that is slightly narrower in diameter than your long wood screws.
Use the screwdriver to insert the long screw through the center hole of the bracket and into the table leg. Make sure that the flat part of the bracket faces away from the wood of the table leg.
Repeat steps one through four for the other three table legs.
Rest the tabletop on the floor so the bottom of the tabletop faces up.
Decide where to put the table legs on the tabletop, at least 2 inches from each corner. (A tape measure could be useful here.) When you're satisfied with where the legs should go, set them into place and use the pencil to mark where the four outer holes in the bracket rest on the bottom of the tabletop.
Move the legs out of your way and drill pilot holes in each of your pencil marks from step seven.
Use the screwdriver to attach the bracketed legs to the tabletop. The screws come in from the underside of the bracket (what will be the underside when the finished table is upright), through the bracket holes and into the tabletop.