I typically do this with short, patterned scarves, but I decided to do the tutorial with this purple one so that the pattern doesn't make it difficult to tell which strand is which.
Step 1: wrap the scarf around your neck where you want it to lay and knot it once.
Step 3: loop the end that you just brought over the other end, through the neck hole.
Step 4: Bring that end out and over the loop.
Step 5: Take the other end and bring it over the end that you just used. Just like step 2.
Step 6: bring that end through the loop just like step 3
Step 7: Bring that end over the loop. Just like step 4. Keep repeating steps 2-7 until you run out of scarf to use.
Step 8: when you finish with the braid, pull the top and the bottom ends of the braid to stretch it out. This will really show the braid detail and then tie the two ends in a not to secure and you're done!