When inserting a composition, you are actually copying its nodes into the currently open composition. The composition being inserted is not affected by the insert operation.

To insert a composition:

1. Select File > Open or press Ctrl + O (for Windows and Linux) or Cmd + O (for Mac OS).
2. In the File Browser that opens, select a composition and drag it to the Player or Schematic view.
3. In the Gate UI that appears, swipe west to insert the selected composition in your current composition. All nodes from the selected composition are inserted, except its output nodes.