The first step in taping your drywall is to make sure that all rough edges are smooth and paper edges that are exposed are ripped smooth. You will need a bag of “Hotmud” or another type of quick set mud to fill all the damaged holes and horizontal joints where the sheetrock meet. Other areas to “fill” with quickset mud are areas where the sheetrock does not feel smooth when you rub your hand down the joint.
Next after the “hotmud” has dried give it a quick sand over the area to smooth it out. Do not over sand to expose the joint you filled. Mix your “taping” mud with a little water, needs to look like pancake batter. **Important to note, Taping mud has more glue than all-purpose, never, unless you have to put the tape on with all-purpose because of this reason**. Unless you have the proper tools to put tape on ..ie..banjo or bazooka, spread the mud on the joint with a 6 inch taping knife, enough to cover the joint and a 2 inch piece of joint tape, but not so much mud that it is falling on the floor. Wipe down with an 8 inch knife, and let dry. Fill all screw holes with a coat over them.
Next lightly sand down the rough areas, during the walk through sanding down the rough areas look for bubbles in the tape. These are air pockets that did not get enough “Taping” mud under them. Cut out or pull tape off these voids and retape. After the walk through apply the second coat with an 8 inch knife, and come back and wipe it down with a 10 inch knife. Go over the angles with a 6 inch knife with mud on both sides of the tape. If you have the tools go over the joints with a 10 inch taping box. Second coat the screw holes. Let dry completely.
Next, again lightly sand rough edges, and repeat step 3 this time with 10 inch knife spreading the third coat on and wiping down with a 12 inch knife. Or use a 12 taping box to apply third coat. On the horizontal joints, apply mud 12 inches on both sides of the joint leaving the middle of the second coat untouched. Coat the screw holes again. Let dry completely.
Last and most important step is to come back after all is dry and use your bare hand to feel all joints smoothing them down with very fine sandpaper. Do not sand so hard that you expose the tape you covered with the 2 coats of mud. You should not feel a hump in the wall where you applied mud, if so sand down smooth or apply mud to the edges of the dried third coat flaring out the joint with mud.