Register for free membership on a website that allows you to create music from scratch. You may want to explore popular sites like JamGlue, Loop Labs, Dubstep and JamStudio and see which layout suits you best. A variety of options exist, but try to choose a website that offers multitracking capabilities, or the ability to add and edit each instrument separately on its own track. If you do not know what a multitrack mixer looks like, find one that resembles a series of horizontal recording spaces, like long bars, all stacked on top of one another. Usually each recording space will have a name like "Track 1" or "Audio Track 01."
Choose a tempo for your song. Most music mixing websites should contain a "Tempo" indicator somewhere on the mixer, that allows you to speed up or slow down your song by moving a small slider or entering a number into a box. If you want to create a fast beat, try setting the tempo between 140-160 beats per minute. If you want a slow beat, try setting the tempo between 90-110 bpm. A mid-tempo beat should fall somewhere in between the fast and the slow range.
Place a percussion or drum sequence on your first track. Your program will contain a loop browser somewhere on the mixer, which allows you to explore a variety of pre-recorded music samples that you can incorporate into your beat. To hear what a particular loop sounds like, just click it one time. When you find a percussion sequence that works for you, drag it onto the first track at the top of your mixer. If you click the right edge of the loop and drag it to the right, you can repeat it as many times as needed.
Add a bass loop. After you have the percussion aspect of your beat, you should try adding your bass. Continue exploring the loop browser and find a bass line that works for you. To layer it with your percussion, just drag it onto the second track and place it directly beneath your percussion loop, so that the two loops are parallel to one another. This will cause the two loops to play simultaneously, giving you a drum and bass combination.
Add additional loops as needed. Depending on the type of beat you want to create, you can add piano sequences, synthesizer leads, sound effects, guitar riffs or anything else that you see fit. Just add them to the mixer exactly as you did your first two tracks, by dragging them onto blank tracks and setting them parallel with your original loops. You can layer as many loops as you want, but if you add too many, your beat may start to sound distorted as a result of too many different sounds competing for the mix. Start with five or six tracks and see how your beat sounds.
Mix your music. With all of your loops arranged on the browser, you can now add effects like echo and reverb, or move different parts around, like placing your keyboards in the right channel and your sound effects in the left channel. Some programs will even give you advanced editing options like EQ, which allows you to isolate the frequencies of different tracks and change the amount of bass, treble and mid tones. Your program's editing options will appear alongside each individual track, so try different effects to get the best sound.
Save your work. Somewhere on your browser, you should see a "Save" button. This will allow you to give your beat a title and save it to your hard drive.