Installing stereo and amp

Hi, I am trying to install an Alpine 445u amp with a new Sony stereo. I have found all sorts of diagrams online for this seemingly simple installation. But, I am confused about how power gets to the stereo! The diagrams show power going to the amp, speakers being attached at the amp, the blue remote turn on going from the amp to the stereo, and the RCA cables going from the amp to the stereo. No power to the stereo? No other wires going to the stereo that aren't from the amp? My stereo is not turning on. I have traced the power wire (attached to amp) all the way back to the battery and it seems to be OK. With this Amp, I can't really tell if it is on. However, from my reading I guess it isn't supposed to turn on until the stereo signals it to (reason for the blue turn-on wire).

Also, concerning the inline fuse, the amp has a 15 amp fuse. The stereo has a 10amp fuse. Since (if) the power only goes to the amp, should I just use the amp rating to calculate the inline fuse, or should I add the stereo and amp together to get the inline fuse amperage?

This is an old 82 VW Vanagon that had the stereo yanked out of it before I purchased it. I have cleaned up the wires and am back down to the basics. So, there are no weird factory installed components with this install!