Perhaps you have once asked yourself how iD gets that neat text about the secret on Deva Station (q3dm11) onto the monitor.
That's easily done.
As activator of the text you can either use a trigger_multiple entity, a button or an item.
For this example create a brush, place a common/trigger texture onto it and convert it into a trigger_multiple.
Now add a target_print entity to the scene (you might have a target_smallprint entity in your entity list, which is only working with Defrag, but has meanwhile the same effect as a target_print).
First select the trigger, then the the target and press Ctrl+k to connect them.
Select the target_print and open the entity window by pressing n.
As "key" type message and as "value" the text you want to be displayed.
In Defrag the text is automatically smaller and more precise than in baseq3.
Of course you can also use the colours defined in Quake 3 Arena. (see defi file tutorial)
It is also possible to write longer texts including breaks. Use "\n" for each break.
The spawnflags are self-explanatory. If no flag is ticked then everyone in the game will get the message.
For example, if you want the players to know that the railgun has been taken. Furthermore that can be accompanied with a sound (see target_speaker).
In Defrag the message is automatically shown to the player activating the text.
The target_print is useful if you want to let the player know that there are e.g. 4 buttons left to activate to open the door. Or to narrate a small story like in sock's just published map "The Edge of Forever".
You can also create nice little effects like "typing".
Of course you can also overdo it: