Event Graph Basics: BeginPlay, Nodes, and Wires Explained

The one idea that makes Blueprints click

If your last lesson left you staring at an empty Event Graph wondering what to actually do with it, you're in exactly the right place. Almost everything in Blueprints comes down to one simple sentence: an event happens, and in response, actions run. The player presses a key — fire a gun. Two things touch — pick up a coin. The game starts — set everything up. That's it. Master that pattern once and every Blueprint you ever read suddenly makes sense.

In this lesson we'll use the most fundamental event of all, Event BeginPlay, which fires once the instant the game starts. We'll hang a single action off it — printing a message to the screen — so you can see, with your own eyes, your Blueprint running. Tiny result, huge moment: it's the first time your logic actually does something. Let's get it on screen.

Don't worry about memorising menus. The goal here is the mental model, not the trivia. Wires, pins and nodes will feel strange for about ten minutes and then become invisible.

Events trigger actions: the model in plain English

Picture a row of dominoes. The first domino is the event — Event BeginPlay. When the game starts, something flicks it. The white execution wire is the line of dominoes: it carries the 'go!' signal from one node to the next, in order, left to right. Each node it reaches does its job, then passes the signal on.

Coloured data wires are different. They don't make anything happen and they have no order. They just hand a value to a node that asked for one — like passing an ingredient to a chef who's already cooking. White says WHEN; colour says WHAT WITH. Keep those two jobs separate in your head and Blueprints stop being intimidating.

Make your Blueprint print 'Hello' when the game starts

Open the Blueprint you created in the previous lesson (or make a fresh Blueprint Actor) and click the 'Event Graph' tab at the top. Work top to bottom — each row stays ticked even if you close the page and come back.

1. ✓
   1Find Event BeginPlay (it's probably already there)

   When you open the Event Graph of a brand-new Blueprint, Unreal often drops a few faded grey event nodes in for you — including 'Event BeginPlay'. Faded just means 'placed but not wired up yet'. It has a single white output pin on its right edge with a small arrow.

   If you don't see it, right-click on the empty graph, type 'BeginPlay' into the search box that appears, and click 'Event BeginPlay' to place it.

   TipRight-click on empty graph space is your universal 'add a node' move. The search box filters as you type — you almost never scroll the menu.

2. ✓
   2Drag off the white pin to add the next action

   Left-click and hold the white output pin on the right of Event BeginPlay, then drag the wire out into empty space and let go. A search menu pops up — and crucially, it's already filtered to nodes that can connect to an execution wire.

   This 'drag-off-a-pin' habit is the fastest way to build graphs: the wire connects itself the moment the new node appears, so you never have to wire it by hand.

   TipDragging off a pin pre-filters the menu to compatible nodes only. It's both faster and a great way to discover what's even allowed to come next.

3. ✓
   3Search for and place Print String

   In the menu that opened from your dragged wire, type 'Print String' and click it. A new node appears, already joined to BeginPlay by a white execution wire — the arrow flows from BeginPlay into Print String.

   Print String is the beginner's best friend: it slaps a message on the screen so you can confirm a piece of logic actually ran. You'll use it forever.

   TipIf Print String doesn't show up, untick 'Context Sensitive' in the top-right of the search menu, search again, then re-tick it once you've found the node.

4. ✓
   4Type your message into the In String field

   On the Print String node, find the text field labelled 'In String'. It defaults to 'Hello'. Click it and type whatever you like — for example 'It works!'.

   That little text box is a coloured (pink) data input baked right into the node. You could instead drag a pink wire into it from somewhere else, but typing straight in is perfect for now.

   TipNotice the 'In String' pin is pink — pink is Unreal's colour for text (a 'String'). Each value type has its own colour, which is how you tell wires apart at a glance.

5. ✓
   5Compile and Save

   Click 'Compile' in the top-left toolbar of the Blueprint editor (the icon turns into a green tick when your graph is valid), then click 'Save'.

   Compiling turns your visual graph into something the game can run. Get into the rhythm of Compile, then Save, every time you change a Blueprint.

   TipA yellow question mark or red cross on the Compile button means 'not compiled yet' or 'there's an error'. A green tick means you're good to go.

6. ✓
   6Place the actor in the level and press Play

   Make sure an instance of this Blueprint is actually in your level — drag it from the Content Browser into the viewport if it isn't. Events only fire on actors that exist in the running game.

   Press 'Play' (or Alt+P). The instant the game starts, your message appears in the top-left corner of the viewport. That's Event BeginPlay firing and the execution wire carrying the signal into Print String. You just ran your first Blueprint logic.

   TipOn-screen Print String messages fade out after a couple of seconds by default. Don't blink — or bump up the node's 'Duration' value to keep it up longer.