There are actually two options to link answers of a certain scene to another scene. The first is by linking to existing scenes, the other is by creating a scene while linking.
Link two existing scenes
When you have two scenes on the canvas, you can link these together by pressing on a letter of an answer (for example 'A') and to drag your mouse towards another scene. Release when you hover above the other scene and the two scenes are linked.
Once an answer is linked to another scene, you can see the corresponding letter is filled up. Directly after linking a menu pops up to select the amount of points choosing this answer should get. More information about points can be found here.
Creating a scene while linking
This is roughly the same as the previous method, but you only need one scene. When dragging an answer and releasing on the canvas (oppose to on a scene) you create a scene and link to that scene at once.