Installing sub&amp 2004 Corolla CE

I'll be replacing the factory radio with a single din stereo and running wire to the trunk for a sub/amp set up. I just wanted to know if anyone has any tips on getting the power through the firewall? Or is there a way I can tap into the fuse box? Any tips would be great thanks.

Never mind. Found a rubber booty on the passenger side next to the fan box. I'm so amazed at how easy the body panels come off and go back on on this car. I'm still confused why they installed the driver side fuse box the way they did. How do you even get to the fuses let alone see them.