OK, I guess now I understand your questions. LaTeX basically contains 3 major areas --- (1) Typesetting, (2) Fonts, (3) = Programming. To master all of them is not an easy job, requiring perseveran= ce and constant curiosities.=20 The programming part remains largely open for users to develop their own co= des to suit their needs. Some will write useful packages (like subroutines = in other programming languages) for users to call and solve their problems = on typsetting or font-related issues. LaTeX provides two formats (class and= style) for code developers to use.=20 If it is a "style" file, you need to use the command \usepackage{...} to ca= ll it, but if it is a "class" file, you can put the "class" name into the \= documentclass{class name} directly. For example, "exam" class and "beamer" = class are two very popular packages in academics, written not by Profs. D.E= .. Knuth or L. Lamport, but by others.=20 So if it is a class-package file, then \documentclass{package name} is my a= nswer to your question.=20 To become a package writer requires a certain knowledge on LaTeX, I would r= ecommend those to read (and can be found in Internet) these two as a starte= r. 1. usrguide.pdf 2. Minutes in less than hours: Using LATEX resources by Jim Hefferon 3. Study some short package files to accumulate your skills.=20 4. Write your own class or style file solving your own problems. Such as a = thesis class/style file that could benefit many students to come. Or design= your own stylish business card that is not standardized. Or your own CV wi= th amazing layout that attracts eyes of sharp bosses. =20 Yes, there are many users who think TeX provides more flexibility than LaTe= X does, which is true in my view. But TeX has a higher learning curve to cl= imb. To master it takes dedications. Most TeX commands can be understood by= LaTeX, so .... I would learn LaTeX first.=20 To take a peak, the following is introductory A Gentle Introduction to TEX A Manual for Self-study=20 by Michael Doob, Department of Mathematics Last but not least, I am, by no means, an expert in LaTeX, simply expressin= g my humble opinions. =20