Attach the dough hook to the KitchenAid.
Put the flour in the Kitchenaid mixing bowl. Put the yeast on one side of the bowl and the salt on the other side of the bowl (otherwise the salt can kill the yeast). Add the margarine.
Lower the dough hook and set the mixer on speed 2. The ingredients will start mixing together. Don't worry if the margarine doesn't look to be mixing in, it will eventually.
Add the tepid water a little at a time until the mixture forms a ball of dough. You probably won't need all the water.
Once you have a ball of dough, let the KitchenAid knead the dough for approximately 4 mins.
Stop the Kitchen Aid and check the dough. It should be soft and elastic (you can check this by pulling on a piece of dough). If it isn't then let it knead for a bit longer.