Can I play tracks from iTunes or YouTube?

Yes. Audio comes into channel 1.

Some files, such as Apple Music tracks, can only be played with certain players so you may not be able to play tracks like these. Depending on the situation, you may have to change the audio setting on your PC/Mac. You can change the setting as follows:

■ Windows
Click the speaker icon in the lower-right corner of the screen, then click [Speaker] to switch to [Line DJM-S7].
When using Windows 8.1 or earlier, set [DJM-S7] as the default device when referring to [1. Check the default device selected in the [Sound] panel] in Case 3 of the guide [here].
*The guide is for rekordbox users. However, you can follow the instructions the same way.

■ Mac
Open [System Preferences] -> [Sound] -> [Output] -> [Sound Output Device] and select [DJM-S7] as the sound device.