I honor your curiosity!
The FM transmitter components are contained in the cabinet, but the diagram only represents the final amplifier stage. The FM signal actually originates in an "exciter" and I believe those are the small rack items at the bottom. There are actually two of these, probably for reliability reasons. They produce only low power, I'd guess 8 watts based on that label at the top.
The block diagram is an amplifier that boosts the signal power up to several thousand watts (4.5 kilowatts according to that label again). The block diagram begins with a pair of switches to select which of the two exciters is in use. The other one is routed to a resistor that serves as a "dummy load".
The large vertical block with the "division" symbol is a divider that splits the exciter power into 5 different amplifier circuits, then the "summing" (greek sigma) box recombines them. Why? I'd guess so each amplifier only has to produce about 1 kW, and that's easier and cheaper than building a single 5 kW amplifier. These amplifiers have variable gain (the slanted arrows) so the station can change the power level.
After the amplifier signals have been recombined, there's a filter. That's the box with the sine wave pictures, some crossed out and one that's not. This keeps unwanted harmonics from getting to the antenna.
Finally, there's a coupler that picks up a bit of the output signal, measures it, and sends it back to the power regulator. This is compared with a "desired power" setting, and if they don't match, the amplifier gains will be automatically adjusted.
If you find electronics interesting and want to tinker with it, there's not much opportunity at a broadcasting station. Look into amateur radio. Licenses are easy to get, and equipment is low in cost. Best of luck!