Assembly guides, or assembly manuals, are a form of instructional guide, which in turn is a subset of technical manuals. These guides are a type of technical writing intended to provide the user with information on the correct assembly of a product. Like all technical manuals, assembly guides are a text-based format in which illustrations or diagrams are employed to work with the text for better comprehension of the material. For some products, especially those sold internationally, the text is increasingly minimized in favor of illustrations, though this can and does cause confusion when customers are unable to decipher what the illustration is intended to show and there is no text to explain whether arrow B-3 is pointing at hole A-2 or D-12. Lego instructions are particularly famous for including no text, making them internationally appealing and child-friendly.

Assembly guides are generally arranged in a fairly standard order. At the beginning, the guide lists the pieces and components of the product and indicates any tools that are necessary for assembly. There is frequently a warning about health or safety risks associated with assembling the product. Then, the assembly of the product is depicted in a series of chronological, incremental steps that the user must follow to achieve the finished product.