LCD on modern transceiver, with spectrum displayed of nearby stations. The band-scope at the bottom helps ham operators find signals.
Many hams can be on the same frequency, but it depends on the propagation factors.
VHF and UHF are line of sight, so many hams can be on the same frequency in one state. Hams often do a lot more listening than transmitting. Often, they listen for another ham that identifies the station being in a sought-after county, state, or country. Hams collect confirmations of contacts using QSL cards . Hams collect the QSL cards and receive awards for contacting so many countries on certain frequency bands.