This chapter explores the necessary steps for assembling parts in a bottom–up approach. It presents an exploded view is useful to help the people who are involved in the assembly to figure out how to go about assembling the parts. This information is normally included in the product guide/manual. Assembly modeling is the combining of part models into complex, interconnected solid models. There are two well-known approaches to assembly modeling: top–down and bottom–up. Mates create geometric relationships between assembly components. There are three types of mates that are available in SolidWorks: standard, advanced, and mechanical mates. There are two ways to start the assembly mode of SolidWorks: from a new SolidWorks document or from an existing part that students wish to place first in the assembly document. Each mate is valid for specific combinations of geometry. The controlling display performance in SolidWorks is split into two categories: central processing unit processing and graphics processing unit processing.