This is one of the many ways to braid challah. If you'd like to see more methods, please check out my other Instructables.
We'll start with your favorite bread recipe. We'll do our braiding after the dough has risen once.
Cut your dough into 4 equal parts.
Roll the dough out into ropes of equal size. I find the easiest way to make the ropes even all the way across is to roll from the middle of the rope and press and move your hands outward as you roll.
Take all four ropes and pinch them together at the top.
Step 2: The Braid
Move rope 1, between 2 and 3.
Now pick up 3 and move it where 1 was.
Now we'll count our ropes from the left 1, 2, 3, 4.
Pick up rope 1 on the left, and move it between the new 2 and 3.
Pick up the new rope 3 and move it where the left rope 1 was.
Go back to the right and count from the right as above and continue braiding by switching back and forth between left and right.
Keep braiding until you get to the very end. Pinch the ends together and tuck them under your braid.
Tuck the top too, if needed. Let your dough rise again before baking.