Questions to ask yourself before you start :

What is the reference component ?

The body equipped with self-lubricating bearings, therefore a subassembly.

What are the complementary components ?

The front and rear axles, identical in our exemple ; therefore the subassembly CE_Essieu (Axle) needed two instances :
 

To view the different stages of the example, click in order on the boxes in the graph opposite or on the arrows at the top of the page.