Tie a knot at the top and stick it to your work surface. Let’s call the strings A, B and C. Take string A and place it over B. Now A is in the middle. Take string C and place it over string A. Now the strings are like this: B, C, A. Continue braiding in the same order: place the left string in the middle, then the right string in the middle and so on. At the end you can make a knot to secure the braid.
You can also make braids using more than three strings. Here are some examples:
A four string braid:
A six string braid:
A seven string braid:
An eight string braid: