Component arrays and mirrors
A row of identical parts is placed by an array, not by copying.

- Linear array: select the part, set the count and the direction above, the spacing at the geometry.
- Circular array: the count and the axis above, the angle at the geometry.
- Component mirror: select the part and point at a plane.
One feature instead of a handful of copies
The copies live in one node: the count and the spacing are edited in one place, and deleting the array removes every copy at once. Copy a part by hand twelve times and one edit becomes twelve, and you will forget one of them.
That is also why a copy of an array is not deleted on its own: the array drives its position, and it would come back on the next rebuild anyway. The whole array is deleted instead.
A mirror is not a copy
A mirrored part stays tied to its source: a change to the original carries over to the reflection. For a left-and-right pair that is exactly what is wanted.