Hi and welcome,
Import:
File > Import > Audio File. Select all (2 or 3) files in the window, and open. Cubase will ask you, if you want to place them to one track, or separated tracks. If you want to mix them together, use separated tracks. If you want to place the one after each other, use one track.
Edit:
To cut the events, use Split (scissors) tool, or drag and drop by using the square in the bottom corners of the events.
Export:
Set Left and Right Locators, File > Export > Audio Mixdown.