Guide for the use of the code. The first three modes deal with the determination of the Fourier coefficients when expanding in series the perturbing potential (FCgrid and FCforDF), and the calculation of the perturbed distribution function (PertDF). PDFdisp allows this function to be displayed as a distribution of velocities. ALL regroups these modes into one, but it is not recommended because of the need to check the Fourier decomposition. EPI directly calculates the perturbed distribution function under the epicyclic approximation, as explained in M16. The FUNCTIONs correspond to different operations required before using the MODEs. DFpos creates the file storing the positions at which the distribution function will be determined. FCorb creates several files containing positions from the many orbits needed to calculate the Fourier coefficients in the FCgrid step.