Short answer: Hover between two rows in the timeline and a + appears; click it to open the insert palette. Pick a verb and Forge inserts a working event at that spot immediately and opens its editor. Media verbs (background, music, sound, video) open the asset picker first, and verbs that need something your project doesn't have yet - a variable, a sprite - create it for you inline. Every inserted event is valid from the moment it lands.
The + between rows
The insert point follows your pointer: hover the gap between any two rows and the + gutter appears there. At the end of a scene (or in an empty one) a dashed ghost card plays the same role - click it to add the next event. Inside a choice, the gutters add events into an option's branch; to add another option, use + Add option in the choice's editor.
The insert palette
Clicking + opens the palette: 39 verbs organized into 11 categories - Story, Sprites, Background, Stage, Video, Effects, Style, Audio, Flow, Logic, Monetize - each entry with a one-line description of what it does. A search box filters across everything, a recently-used row keeps your last few picks one click away, and the whole panel is keyboard-navigable.
Most verbs insert instantly
Pick a verb like narrate, dialogue, choice, pause, or jump and the event lands right away with a sensible starting value - a dialogue line arrives with a speaker, a choice arrives with a prompt and starter options - selected and with its editor open so you can shape it immediately. If the new event is something visible, the stage moves onto it so you see it in the game as you edit. A default you never touch simply stays until you delete or undo it.
Media verbs pick the asset first
Background, music, sound, and video need something to show or play, so they open the asset picker before creating anything. Choose an asset and the event is created with it; cancel the picker and nothing is added to your scene.
Verbs that need something that doesn't exist yet
Forge never blocks an insert on missing setup - it offers to create the missing piece on the spot:
- Set or when with no variables yet opens a small create-a-variable popover; the new variable is created and the event uses it.
- Sprite verbs with no sprites yet create a placeholder sprite for you on the spot and open it in the Sprite Manager, ready to refine.
- Call needs a scene to run: it arrives pointing at another scene when your project has one, and its editor is where you pick the target.
Every insert is valid
There is no way to insert a broken event. Each verb's starting form is a complete, working story line - which is why nothing red appears when you add one, and why you can keep playing the scene the moment it lands.