I use view cameras, and often use tilt/seing and rise/shift. I almost always use rise.
To keep the perspective constant, you keep the film plane vertical. Shifting left-right or rising up-down (either or both the lens and film) changes the region mapped onto the film plane.
Tilting the lens board with respect to the film plane changes the plane of best focus, but does not change the perspective. It may change the exact region mapped onto the film plane, depending on the tilt axis. This is typically done to keep the meadow in front of you and the snow-capped mountain in the background in focus, allowing some defocus where the mountains reach the ground.
If you tilt the film plane, you do change (or distort) the perspective. If the film plane is tilted backwards, for example, the vertical parallel lines on skyscrapers will converge on the film.