diff --git a/src/sa/model/index.md b/src/sa/model/index.md
index 405efe0..c7dc653 100644
--- a/src/sa/model/index.md
+++ b/src/sa/model/index.md
@@ -692,11 +692,11 @@ skinparam defaultFontName Courier
 @enduml
 ```
 
-Use case: a user alters manually the state of a device in the UI, and the device updates accordingly.
+Use case: a user alters manually the state of device 'D' in the UI, and the device updates accordingly. Device 'D' is not part of any defined trigger.
 
 ```puml
 @startuml
-title Process View: Sensor triggers trigger and scene application
+title Process View: UI updates state of device
 
 participant "Smart device 'D'" as D
 participant "Smart sensor 'S'" as S
@@ -708,7 +708,48 @@ participant "Trigger and Automation DB" as TDB
 participant "Scene Engine" as SC
 participant "Scene DB" as SCDB
 
+UI -> DI: request state update
+DI -> D: apply new state
+D -> DI: report successful application
+DI -> DIDB: store new state
+DI -> UI: display new state
+DI -> T: report latest device state
 
+skinparam monochrome true
+skinparam shadowing false
+skinparam defaultFontName Courier
+@enduml
+```
+
+Use case: a user through the UI defines a new automation, defining a matching new trigger and a new scene for it.
+
+```puml
+@startuml
+title Process View: UI defines new scene, trigger and automation
+
+participant "Smart device 'D'" as D
+participant "Smart sensor 'S'" as S
+participant "User Interface" as UI
+participant "Device Engine" as DI
+participant "User and Device DB" as DIDB
+participant "Trigger and Automation Engine" as T
+participant "Trigger and Automation DB" as TDB
+participant "Scene Engine" as SC
+participant "Scene DB" as SCDB
+
+UI -> DI: fetch device registrations
+UI -> T: fetch defined automations
+T -> TDB: query automations
+UI -> T: fetch defined triggers
+T -> TDB: query triggers
+UI -> SC: fetch defined scenes
+SC -> SCDB: query scenes
+UI -> SC: store new scene
+SC -> SCDB: store new scene
+UI -> T: store new trigger
+T -> TDB: insert new trigger
+UI -> T: store new automation
+T -> TDB: insert new automation
 
 skinparam monochrome true
 skinparam shadowing false