So far, everything you have played has involved playing one note at a time. However, when playing the drumkit it is common to play two or more notes at the same time. This involves coordinating the limbs so that the drums are hit at exactly the same time.
A good way to start developing this skill is to play quarter notes on the bass drum and alternate the hands on the snare drum, as shown in the following example. As always, practice this with your metronome or drum machine and listen carefully as you play and make sure your notes are exactly together and not "split". Once you are comfortable alternating RLRL, try starting with the left hand instead (LRLR). Then try LLLL etc. and RRRR etc.
The next thing to do is alternate your hands between two or more surfaces as shown below. In the first line of this example, the hands play only the ride cymbal and the snare drum, while in the second line, they move between several surfaces. Once you can do this one, experiment and create some of your own drum parts using this technique.