Step 1: Braiding
Now separate a small section on either side of the head. I am starting on the left and braiding to the right, but you can do it the other way too.
Then break that small section into thirds.
Start the braid by taking the left section and passing it over the middle section. Then take the right section and pass it over the new middle which used to be the left section.
Now I take the left section and add in a bit of hair from the large chunk to the right. Make sure you add the new hair under the other two sections. Then braid that hair in by bringing it over the middle section.
Then add a little bit of hair from the bigger piece to the strand on the right. Braid this strand into the braid in the same way.
Continue doing this until you run out of hair in the large right section. Then just braid the rest of the way down without adding in any more hair.