Blog Tour? Where Do I Even Start?

Okay, need some advice for a newbie author. I suppose at some point I need to start a blog tour schedule. The problem is, how do I even begin? Is it something I just go around to my favorite blogs and ask someone if I can have a date on the calendar? Or is this something my publisher starts?

I honestly have no idea how to do this but I do know that I'm probably already behind the power curve if I'm less than 90 days until my book comes out and I don't have anything scheduled yet, right?

What does a blog tour look like? How do you schedule it? And who do you contact?

Anyone with information, I'd appreciate advice, guidance and direction!