In this seminar, the recent progresses made on the description of small and large amplitude dynamics in nuclei will be reviewed. State of the art mean-field and beyond mean-field approaches including superfluity will be introduced. These techniques will be illustrated for several phenomena like transfer, fusion reaction or the fission process. Many aspects of the structure and reactions between nuclei can be described in a mean-field description where nuclei are treated as quasi-independent particles moving in an average field. In some cases, however, we anticipate that a single mean-field cannot grasp the full complexity of nuclear dynamics. A possible solution to these cases, is to go beyond mean-field by mixing-up several mean-field trajectories. Two approaches beyond mean-field will be introduced. The first one is based on the random sampling of initial quantum fluctuations followed by independent mean-field evolutions. This approach is able to reproduce observed mass distribution and kinetic energy of nuclei after fission. The second approach is more ambitious and relies on the quantum mixing in time of mean-field paths, leading to a complete re-quantization of the collective motion. Although this project is still under development, it will shown how this approach might help to understand the transfer process between two superfluid nuclei.