Relax your bow in the double bow press and remove the old string. Remember to which post the string was attached on the sight-window side of the cam.
Inspect the new string for any defects or flaws. If you find any, discard it and use a different string.
Attach an end loop of the new string to the post from which you took the old string. Wrap the string around the bottom and around the top of the cam, and pull it toward the other end of the bow.
Wrap the string over the top of the concentric idler wheel on the opposite end of the bow, and pull the string back to the cam.
Wrap the string over the top and around the outermost groove on the side of the open side of the cam. Attach the end loop to the post.
Make sure the string is secure in its groove and carefully release the double bow press.
Apply wax to the new string.