Can anyone help me start building my own poweramp?

In my high school and college days (1950s) I built several amps, and an electronic crossover from schematics. In one case I used a metal bread baking pan for the chassis! The stuff sounded OK and I sure learned about electronics. Somehow I managed not to electrocute myself. With tube amps you do need to respect the output tube plate voltage which, even for a small amp, will run around 300 volts.

Have fun.
.

Tube would be a whole lot easier to work with. For an initial project I suggest that you rebuild an old dynaco amp. If that goes well you will have learned a bit about how amps work, and aquired soldering skill. Solid state amps have components that are easy to damage during assembly, and some ICs are near impossible to solder with manual tools.

Another possibility is to put together a digital amp using the UcD modules from Hypex. This will teach you little about amps, or soldering, but you will end up with a first class piece of gear.