Step 1: Importing Clips
First click "File" at the top left corner of your screen.
Mouse over the option "Import"
A side menu will appear, Select "Media" which will open up a File Browser
Select the files you wish to import on the File Browser
After a short loading time, The files will show up in the media tab on the left side of the screen.
Now you can click and drag those imported clips onto the Timeline tracks to begin editing.
The next step will explain the usage of the Timeline tracks.