Please help me understand/clarify time dilation?

As you speed up to speeds approaching the speed of light, the traveler slows down because natural processes responsible for his rate of time are based on the speed of light too. For this reason, he must slow down because in order to maintain the same clocking speed would require that his very atoms exceed the speed of light. All of the matter that you are made of is traveling at the speed of light already and this is why E=MC2. It is however, traveling in circles. You can't travel at the speed of light and also still be travelings in a circle at the speed of light too.