I have two 30 meter sitka spruces that have fallen in my yard. I'd like to process them into usable planks ideally as long as possible only using hand tools. Can someone give me a step by step on how to do this? I've been reading about riving and hewing and splitting but I'm not sure how it all fits together.
If you want to use hand tools only you don't have a lot of choices. In the olden days you would most likely hew each log into a single timber (i.e. in building a mighty timber-framed barn, or a ship) rather than sawing it into planks. See Roy Underhill's TED talk for a brief demo of the technique. If you really want to saw it into planks with hand tools you need to get together with a friend and set up a saw pit. Even a water-powered or wind-powered sawmill would seem to be outside of your requirements.
If you really want to get into preparing your own lumber, you will want a powered sawmill of some kind. The most common type is a bandsaw mill and I won't mention any brand names but you can do a search for those. They come in all kinds of sizes, some small enough to be portable, and essentially you're looking at a big gas-powered bandsaw that moves along a track. You set the log down and move the bandsaw down the length of it.
You have another in-between option and that's an Alaskan chainsaw mill. This is a kind of frame or rack that you bolt onto your chainsaw and can be used to saw flat planks off your fallen log right where it lies on the ground. Looks like a lot more effort per board foot than a bandsaw mill, but if you only want to saw these two trees and no more, it might be a good inexpensive option.