If you are using a mouse: Click in the box, hold down the left-click button, and sign your name by drawing it with the mouse.
If you are using a trackpad: Click in the box, hold your index finger down on the trackpad, sign your name by drawing it within the box, and when you’re finished, release the trackpad.
If you are using a trackpad: Click in the box, hold your index finger down on the trackpad, sign your name by drawing it within the box, and when you’re finished, release the trackpad.