Well you know E=mc� ?atomic bombs? destruction of matter releasing energy?
Well it works in reverse too. Smashing protons together with an immense energy generates particles - trouble is you have no control over which particles and there are thousands of possibilities.
So first you have to detect what particles are produced and at what energies. That means you have to monitor every bit of space around the event.
At the LHC this is done by ATLAS the worlds largest scientific instrument
http://www.physics.upenn.edu/research/images/a tlas_nov2005_v2.jpg
Remember every shot can have many many interactions with particles flashing in and out of existance and interacting with other particles
Then you have to work out if the result is interesting - then you have to repeat - a lot. Finally you may just manage to filter out from the billions of billions of interactions a couple of Higgs events.
This has been in the planning for over 20 years - you wouldn't want to switch it on and go "yup there it is" would you?