How to program meter changes when recording sth in song mode..? I want 3 bars with 7/4 and 4th with 8/4. I don't know how to do it. How to find tempo track?

Thanks!

I am afraid you can't do signature changes within a song in the PC3 sequencer. You can program tempo (speed) changes of course...
What you can do since you want to go from 7 to 8/4's is set your song to 1/4 and "play along"...you should be good!