The tutorials fdor 2014 show to simply activate the track's record, then activate the record. This, so far records my audio input and not the other tracks.
From what you have written, I don't understand what you are trying to do.
Are you trying to record to 6 tracks, say tracks 1 to 6, at the same time with different input, like keyboard on track 1, audio on track 2, guitar on track 3, etc?
You say "record first 6 tracks to a single track." What do you mean by this?
Or, by tracks do you mean songs, like song 1, then song 2, then song 3, etc. all to track 1?
Or are you trying to bounce (see under SMS File Menu) six previously recorded tracks on to a new track? I think this is also called 'internal mixdown'.