Always put Mmbase.sty in the root folder of .tex files (it's a package that I'll use often).
• Mmbase.sty : (short for Mathieu math base), include shortcuts for writting classic math symbols (such as \mathbb{R}) and other handy symbols that are outlined in the file itself ; it also contains every package I found usefull to have.
• base.cls : my baseline class based on the article class with header/footer rulers, section name in the header and page number in the footer + some packages and styling options included. (To use, lookup on Google how to use a custom class in LateX)
• TD.cls : a class that normalize the style I want my tutorials (Travaux Dirigés in French) to look like.
• TD folder : regroup tutorials examples I've created.
• Other folders are self-explanatory.
• Create a practical-style class.