Hm, trying to load a huge ball of spaghetti code into your head is maybe not the best idea.
Personally I would only try to understand the parts I currently need.
Yes, in theory it would be nice to understand everything before you start. It would also be nice to understand quantum physics, and all sorts of other things. In real life, though, sometimes you have to compromise.
I've had the same experience with specifications, btw. Yes, I'll read the whole document before starting. But usually I only really understand it once I start implementing the details. (I am also not convinced that specs of several hundred pages are any use at all).
Personally I would only try to understand the parts I currently need.
Yes, in theory it would be nice to understand everything before you start. It would also be nice to understand quantum physics, and all sorts of other things. In real life, though, sometimes you have to compromise.
I've had the same experience with specifications, btw. Yes, I'll read the whole document before starting. But usually I only really understand it once I start implementing the details. (I am also not convinced that specs of several hundred pages are any use at all).