When scanning a dot using an iPhone, the sweet spot is right at the top, around the camera.
Make sure the dot.thin has been activated beforehand.
Hold the dot to the back near the phone camera and just tap
A link should pop up which will take you to the dot profile
dots can not be scanned while:
the flashlight is ON
the phone screen is OFF
their phone is in Airplane Mode
the camera is Open
For all newer iPhones, released after the iPhone X, no extra steps are required.
*Note that the tap feature will not work while the phone camera is open. As an alternative, scan the custom QR code available on your dot.Profile by using your camera app. A link should pop up which will take you to the dot.Profile.