As the hobbyists who invented radio continued to want to play with it, agreements were made to set aside frequency spectrum for more hobbyists, provided they passed an exam in Radio Wave Propigation, Electronics, and rules and regulatioins.
Hams (persons who have passed a Ham Radio License Examination) can use those frequencies allocated for them for non-commercial communiation.
Hams are technocratic; that is, we respect those who learn and build stuff. Even (especially) easy stuff. We already have that whole "Talking about it" thing down pat; we need more folk who actually "DO" stuff.
Hams have a culture of being helpful and mutually educational.
The Electromagnetic Spectrum
A refresher course on The Metric System, especially these. As ham radio operators, we really only care about these.
milli means multiply by 1 ÷ 1,000 or One Thousanth
micro means multiply by 1 ÷ 1,000,000 or One Millionth
kilo means multiply by 1,000 or One Thousand
mega means multiply by 1,000,000 or One Million
giga means multiply by 1,000,000,000 or a billion
tera means multiply by 1,000,000,000,000 or a trillion
nano means multiply by 1 ÷ 1,000,000,000 or One Billionth
pico means multiply by 1 ÷ 1,000,000,000,000 or One Trillionth