All physical systems, including typography, have inherent structural systems (like the skeletal system of your body). You have been examining how parts of letters combine to form individual letters, which can then combine to form words, phrases, texts, etc.
All images that appear meaningful have inherent structure too. We call the structured arrangement of pictorial elements a composition. Most visual compositions considered aesthetic by humans are based upon a spatial division of thirds.
All types of visual communications, including posters, also have inherent visual structure. This structure enhances a message’s syntax and a good designer uses them to help organize and construct meaning within any form of visual communication. In typography, the most common type of visual system used to structure information is a GRID.
Whether you deliberately create a grid for your design or just wing your composition, once you add an element to a picture frame, you have created a visual structure. Being aware of that structure, and manifesting it as a grid to work with, will aid you in composing messages and laying out designs that will make sense, and also look good.
Use this tutorial to learn how to create a multiple column grid in Illustrator.
https://www.youtube.com/watch?reload=9&v=ow3Z_ULM0cA
This particular application is for web pages and online layouts, but when creating for print, you will want to add margins. To begin, set up document as the desired page size. Be sure you show your rulers. Then manually pull guidelines out from the rulers to set up guides for your margins, top and bottom, and left and right, and continue to set up your columnar grid inside the margins as indicated in the tutorial.
