These extracts from
The Traveller Book (1982), pp 1, 12-13, 15, 98, 123,
state the approach:
The referee presents the situation while the players are themselves the characters in this unfolding novel of the moment. Working together as a team, the players solve the riddles set out before them and play out the situation. . . .
A scenario is like a science fiction novel; the players are given some specific goal and the adventure occurs as they try to attain it. . . . Create a scenario as you would a story, with something to be achieved and difficulties strewn in the path of that goal. Scenarios can be as complex as the referee feels necessary, ranging from the simplest plot devices to complex adventure worthy of a great adventure writer. . . .
The rolling of dice is a convenient way to represent unknown variables or to assist the referee in making decisions. Feel free to modify the results if you do not like the way they turned out. Change a death result to a severely wounded result if you feel a character has behaved heroically and deserves a second chance . . .
Through non-player characters you can give the players rumors, hints, and threats, help them out of tight spots, lure them into tight spots, get them back on the track, lure them away from their objective, and generally help or hind the characters as much as is necessary. . . .
As the adventure progresses, the referee will often have the urge to "help out" the players by providing them with information that they otherwise would not, or could not logically know. This is poor form . . . The function of a referee is to guide, not control. . . . Direct intervention of the referee in a situation is also poor form. . . . The hand of a good referee, like that of a good puppeteer, should be invisible. . . .
Encounters with non-player characters serve as the referee's vehicle for direction and input during adventures.
Settings are places or locations for adventures. Four basic settings for adventures are the ship, the location, the world, and the choreographed novel. . . . The choreographed novel involves a setting already thought out by the referee and presented to the players; it may be any of the above settings, but contains predetermined elements. As such, the referee has already developed characters and settings which bear on the group's activities, and they are guided gently to the proper locations. Properly done, the players never know that the referee has manipulated them to a fore-ordained goal.
Here's an illustration of the approach (just one of many that could be chosen), from the 3E module Expedition to the Demonweb Pits, p 98:
If attacked, the bone naga [Dawnat Sanp] defends himself . . . If after a single round of combat the characters cease their attack, Sanp might accept an apology . . . Either way, go to the E5: Chased Out of the City encounter description below. . . .
E5: Chased Out of the City Once the PCs have the information they need from the ambassador, they will be chased out of the city as spies. . . use the foolowing sequence of increasingly urgent prompts to flee the city. A large part of getting characters to flee is the DM's approach; make it clear to them that staying is suicide.