Complex sentence: He has a second channel, GradeBUnderB, which is a backup channel and has 139,462 subscribers, as of June 20,2016, however there has yet to be a video uploaded to the channel.
Split into simpler sentences: He has a second channel, GradeBUnderB, which is a backup channel and has 139,462 subscribers as of June 20,2016. However, there has yet to be a video uploaded to the channel.