The concept of parts, part instances, and the assembly is carried throughout the Abaqus/CAE modeling process:
You create a part in the Part module; each part is a distinct entity that can be modified and manipulated independently of other parts. Parts exist in their own coordinate system and have no knowledge of other parts.
You define section properties in the Property module and also associate a material with a section. You use the Property module to assign these section properties to a part or to a selected region of a part.
You create instances of your parts in the Assembly module, and you position those instances relative to each other in a global coordinate system to form the assembly. You can also add instances of other models in the assembly.
Abaqus/CAE allows you to create either independent or dependent part instances, as described in What is the difference between a dependent and an independent part instance?. Both independent and dependent part instances maintain their association with the original part. When you modify the original part in the Part module, Abaqus/CAE updates any instances of that part when you return to the Assembly module. You can instance a part many times and assemble multiple instances of the same part. Each instance of the part is associated with the section properties assigned to the part in the Property module.
You use the Interaction and Load modules to complete the definition of the model by, for example, defining contact and applying items such as loads and boundary conditions. The Interaction and Load modules operate on the assembly.
You use the Mesh module to mesh the assembly. You can do either of the following:
The two meshing approaches are described in What is the difference between a dependent and an independent part instance?.
Creating a part or model instance, contains detailed instructions on creating part instances.