The L4 – Logical Activities Decomposition viewpoint of NAF v4 is a diagram upon which you can specify the decomposition of OperationalActivities. In NAF v3 this was called the NOV-5a Node Tree viewpoint.

In System Architect, you connect an OperationalActivity to its parent by moving it underneath its parent until an autoconnection is established – the definitions are updated and the relationship line is automatically drawn.

You can change the way the hierarchy is displayed by right-clicking on a symbol that has child symbols, and then choosing Arrange Children Horizontally > Arrange Children Vertically, or Arrange Children as a Block.