In Revit, a designer can model a system, but by a major steps for working on the project will be much easier.

 

1 – Add items of the system

We can insert items / families into a project using insert family tool

 

then by selector type section at the Properties Palette we place them to specific positions in building.

 

2- Add items to a system.

 

group system component in same system, by specify the type and select items then create a system, put a name to find it any time easily.

 

3- Modeling

will be easy now, we can do it manually or automatically by generate tool