Make the connections between the DJ mixer and your sound system. Plug the RCA cable into the mixer's "Main Out" jack, then into the amplifier's "Line In" jack. Connect the speakers to the amplifier by plugging the XLR cables into the left and right "XLR Out" jacks, then into each of the two speakers.
Play the first record by putting it on the first turntable and setting the needle at the beginning of the grooves around the record's edge. Leave the pitch lever set in the middle to keep the record's original tempo. Use a record that will be at your desired tempo for your entire mix at first. This is helpful for creating a base of tempo to mix from.The genre of records you begin with will vary greatly based on the turntable style that you are going for. Just focus on one particular style of music at first, then attempt mixing in other types later on, once you've got beatmatching down.
Slide the crossfader all of the way towards the turntable that is playing the first record, then place the second record on the other turntable. Place the needle at the beginning of the second record's grooves as well. Nothing from the second record will be heard coming through the sound system as of yet, but that is because you need to cue the second record in before it is heard.
Press the cue button on the second channel of the DJ mixer, then put on your headphones. You will now hear the second record playing in your ears, and the first record playing through the sound system.
Rewind the second record until you hear the first drum kick, then release it at the same time as you hear the first record begin its next drum loop. This may take a few attempts at first, but you will be able to start the two records at the same beat with practice.
Listen to the difference in tempo of the two records, then adjust the pitch lever carefully on the second turntable (the one heard in headphones). Repeat steps four and five until you have the two records matched in tempo.
Slide the crossfader into the middle position to hear both records equally, then over to the side of the second turntable to complete the transition from one record to another on the first turn table.
Press the cue button on the first channel, then repeat steps two through six, now treating the current spinning record as the "first" and the new record as the "second," to keep the mixes going back and forth between records indefinitely.