Start with Hydrogen. Knock off an electron to get a proton which can be manipulated by electric and magnetic fields. Send them into the linear accelerator which has a series of electric plates to speed the protons up and focussing magnets to get the protons to line up nicely. Particles that don't form part of the beam are lost at low energy. Then the beams enter the ring accelerators for the big kick.
The coordination of the control signals is quite fun: it is capable of synchronizing events tens of kilometers apart to nanosecond accuracy.
