Well, you need to know how to describe the three sorts of accelerators:
- Linear Accelerator
- Cyclotron and
- Synchrotron
Know how each works and how they accelerate charged particles.
Then know why they accelerate charged particles: to smash them into other particles to break them apart and see what smaller particles there are that make up the larger ones.
They use particle detectors to view these smashes:
- Cloud Chambers
- Bubble Chambers
- More modern detectors, such as the multiwire proportional chamber
(So, know basically how these work as well, if you can, especially the cloud chamber.)
These smashed apart particles are viewed under the influence of magnetic fields to see how they move. This helps determine their mass, momentum, velocity etc. If you are using Physics 2, there is a nice picture of such an interaction where they found a particle particle they were looking for. It only exists for a short moment, but it was there (as predicted).
The accelerated particles have to be at a certain energy level before they can smash apart other certain particles. It is like throwing a ball at a window. A low energy ball will bounce right back. Hit it with a cricket bat (the accelerator) and the ball will smash right through and you can investigate the nature of the shards that remain.
Does that help? Do you want more specifics?