The LHC will work in a cycle. This process is time consuming for the protons to reach full speed
Each cycle consists of several steps.
1) The magnets are brought to initial energy of 450 GeV per beam which matches the SPS accelerator
2) Then the beam is injected from the SPS until the LHC ring is full.
3) The next step is then to "ramp", the beams are accelerated.
4) Once the desired energy is reached, the beams are kept at that energy for a few hours and squeezed ( compressed to be as thin as possible) so that the collisions at the experiments lead to a best-possible collision rate (luminosity).
5) The beams are then collided. The physics of the collisions are recorded by the experiments, ALICE, ATLAS, CMS and LHCb.
6) Once the beams are depleted, the remains are dumped and the current in the magnet ramped down (snapback). Then the whole story restarts from the beginning.