This guide walks you through creating a simple flyable mission from scratch. By the end you will have a player ship and a hostile wing to fight. The whole thing takes about five minutes.
Launch QtFRED. Go to File › New. The viewport shows empty space with a reference grid. QtFRED automatically places one ship, this is your player start.
Click the player ship in the viewport to select it, then click the Form Wing button in the toolbar. Type Alpha and click OK. The ship is renamed Alpha 1.
Use the ship class drop-down in the toolbar to select a hostile ship class. It will appear in red. Hold Ctrl and left-click in the viewport twice to place two ships. Select both of them (drag a box or shift-click), then click Form Wing again. Name the wing Epsilon. The ships are renamed Epsilon 1 and Epsilon 2 and are hostile by default.
With Epsilon wing selected, open Editors › Wings to open the Wing Editor. Increase Number of waves to 2 and set a short delay between waves. A second wave will jump in after the first is destroyed.
Open Editors › Mission Specs. Give the mission a Title and a short Description. These appear in the mission selection screen. Set music tracks if desired.
Open Editors › Mission Goals. Add a primary goal with a
description such as Destroy all hostiles. Set the completion condition to a
SEXP that evaluates to true when Epsilon wing is destroyed, for example
is-destroyed-delay. See SEXPs for an
overview of the scripting system.
Press Ctrl+S to save. QtFRED saves to your mod's
data/missions/ folder by default. Launch FreeSpace Open, go to the
Tech Room › Mission Simulator › Single Missions, and your mission will
appear there.