SIMP, they're not hard to use once you learn the basic operations of the scanner it'll become second nature in time. The same goes for understanding how trunking works. Once you grasp it, you'll soon see how it makes sense.
Here's a basic way of looking at how trunking works...
In a trunked system, it'll have say 5 repeaters (or frequencies) each radio that is on the system will have all 5 of these frequencies programmed in and will be scanning them. One of the 5 repeaters will act as a CONTROL CHANNEL which sends out a constant stream of data. The control channel acts like a traffic light at an intersection. It basically tells all of the radios what frequency to use to talk to another person on.
Now the thing to remember is that every agency that is on the system are using ALL of the 5 frequencies. FIRE, POLICE, AMBULANCE, PUBLIC WORKS, EOC, ROAD CREWS, etc. whoever they want to allow on the system. How they break them down is by something called TALKGROUPS which is a fancy word for CHANNEL.
Think of talkgroups as a virtual channel. It's not a frequency, but an ID CODE stored in each radio on the system. So when radio 1 has their dial set on the talkgroup Clinton PD Dispatch every other radio that happens to be scanning that talkgroup or have their dial set to it will hear radio 1's transmission.
Now if you just scan all 5 frequencies you'll end up hearing EVERYTHING, and the busier the system is, the harder it will be to follow conversations between each agency. One moment you'll be listening to a pd unit call in a tag, and then your scanner would lock in on a public works crew calling for a dump truck, and then maybe the fire department running hydrant tests...
This is why we have trunking scanners. The trunked scanner allows you to program in those talkgroup ID codes for each agency, so you can keep track of each person that is talking and to who they're talking to.
Another way at looking at trunking is like the cash register of a fast food place... Lets say its rush hour. You have a line of 10 people waiting to be served, but only 1 register open. Well all 10 people have to wait their turn at that 1 register, this would be how a conventional radio system works, 1 frequency for every user. Trunking works like this, you have those same 10 people in line, but instead of 1 register, now you have 5 registers open. So 5 customers can be served at once. As soon as a register becomes available the attendant (like a control channel) allows the next customer to step up to the free register to place their order.
So with a 5 channel trunked system, up to 4 agencies or users can talk at the same time, the 5th channel would be the control channel basically routing where each transmission goes.
I don't know if I got too technical or if you totally missed my point here... Hope you got something useful from it though.
