If you understand a few simple concepts about radio it will help you understand all the other sections and where they fit in.
The "airwaves" are full of thousands of signals coming from radios which include cell phones, radar, shortwave, fm and am radios, computers, household appliances and all sort of commercial radios. These radio waves are forms of "electromagnetic radiation" The airwaves are also filled with natural "electromagnetic radiation" caused by such things as lighting and solar storms. As a radio operator, you will often have a small 5 watt handheld radio trying to receive a message through all this "noise".
Imagine being in a football stadium with a large crowd. Some people are talking. Others are yelling and there is lots of street noise. Your friend is on the other side trying to talk to you. The challenge is to hear what he or she is saying. Impossible you say? This is a lot like what is happening in the paragraph above. The difference is that a radio receiver filters out all the noise to pick out the one frequency your friend is transmitting on and amplifies it enough so that you can hear it. Pretty amazing when you think about it!
Much of the material you will study talks about generating a radio wave, modifying it so that it carries information, sending it through "airwaves", detecting it from a great distance, and amplifying it so that you can hear the information as orginally sent.
In order to understand how this happens you will cover a variety of inter-related topics.
Let's start with Regulations then go on to other topics.