As pointed out above, can you solder? Dave Hunter's book is a great place to start to get a basic overview of what's going on in an amp. Go to amp kit sites. Weber is a popular one, I prefer Triode Electronics; better quality pieces and slightly cheaper. There's a guy floating around here that sells 5F1 kits cheap; no experience with him but looks of decent quality. Build Your Own Clone Pedals has a 5F1 kit with full on instructions in it. I feel that's unnecessary if you do some reading first. The kits are kind of paint-by-numbers, great for getting your feet wet but not much electronics learning going on. But, there is also transformer placement, wiring up heaters, and layout issues you can learn from kits.
First, however, is learning how to solder. If you don't know, look it up on YouTube. Grab some spare wire from your parents (or buy some), cut it, splice it, solder, repeat. It's not hard but takes practice and is crucial as bad solder joints can cause tremendous problems. The more builds you do, the more you learn; think of it as a marathon not a sprint. When you get done building and it doesn't work, that's when the real learning begins. A 5F1 is a good place to start though.