use numpy,pandas,matplotlib,scikit learn

please explain how the method is being used $.$for example : how many categories$/$labels $($discrete or continuous type$)$ and what they are $,$how they are being used or how they are counted $.$About applying PCA and t$-$SNE $,$when it si being apllied and how it has done $.$and its says visualize it too after $.$Please do by yourself not by copying $.$appreciated