The area which contains 'Drums' and 'Drum 'Rack' at the top left of the Ableton screen is called the Browser, because that's where you can browse for instruments and samples and so on: Click 'Drums' on the left (highlighted with a red rectangle in the picture below), then drag 'Drum Rack' onto the title bar of the first MIDI track. Now we'll add a Drum Rack to our first MIDI track so that we can create some drum beats. You can also right-click the title bar of a track and change the name of the track to help you stay organized: Some people prefer to make all of their drum and percussion tracks one color, and their melody tracks another color, and so on, to organize their workspace. My MIDI track in column 1 happens to be green, so right-click the title bar of the first MIDI track and change yours to green as well (highlighted with a red rectangle in the picture below) so it matches mine, to make the tutorial easier to follow.

The colors of each track are random when you start a new Live set, but you can change the colors by right-clicking the title bar of each track. MIDI tracks are for playing instruments, and Audio tracks are for playing digitally-recorded sounds and samples (because MIDI clips store a different type of information than Audio clips do): These are called 'tracks' or 'channels,' and the gray rectangles below the track titles are where you can store clips that you can play using your Launchpad (which we'll do in a moment). When you run Ableton Live 11 Lite, or when you start a new session by clicking File/New Live Set, it starts you off with 4 columns which are labeled MIDI, MIDI, Audio, and Audio (highlighted with a red rectangle in the picture below).

Ableton live lite launchpad