Zen, dude. Strip away all the trappings, and focus on the simple things, and the complex ones shall take care of themselves.
Put the book in your pocket, its a pocket guide, best place for it. Buy some simple patterns laid out up there, go fishing.
Stand by the stream, get your gig ready. Smoke something.
While you're smoking, watch the water, I know you looked at that book before hand, so you've got a feel for what's gonna happen, but its not gospel, and that's why you shoved that book back in your pocket, right?
You start to notice fish rising, and you start to see flies in the air.
You see a thing fly by your face, its about the size of your pinky nail, and glides by gracefully. Its brown, and its got light wings.
You've got two paths to chose from, they both goto the same place.
You whip out your handy book, consult the pages that indicate what's flying around, you make a note of whatever the hell Latin names and common names its probably got, take a look at the suggested pattern, swear coz you couldn't find snowshoe rabbit emerger crippled duns and tie on a cdc emergent dun instead, hoping its good enough. You then begin to flail at the water, knowing full well that crafty brownie down there knows you're offering it cul-de-canard based flies and
not the suggested lepus americanus hind foot toe hair based flies you shoud be using. Also, you looked at the wrong page, and it turns out this isn't blue wing olives and its actually blue quills and sweet babby jesus its all epic fail and and and and wait are they emerging or laying eggs or spinning in and is my hare's foot authentic snowshoe or is it dyed a funny shade and this is not my beautiful house and this is not my beautiful wife where is that large automobile
-Or-
Its about the size of your pinky nail, its kinda light brown. This size 16 adams will do quite nicely, and since we're in the beginnings of the hatch, bonus, it'll lay nice and flat and look like an emerger, until about midway through where it'll still look like an egg layer, and gosh at the end, it'll even kinda sorta look kinda spinnerish.
Bam. Done.
Zen and the art of fly selection.
BTW, that book? WHen you're done, you can consult it to see what you saw. Now you've got a name, you can best figure out which nymph might be more likely next time you swing through, or if you should buy some extra size 12 or size 18 Adamses, or maybe you might want to add some new sulphur parachutes to the collection coz book says that's coming up.
oh, but to less flippantly answer your questions:
1) griffith's gnat goes on top, who cares what's underneath, spring is upon us and its time for things tied in realistic sizes.
2) i don't know what that means either. how about you buy some of them there elk hair caddis flies, life is good. bh probably means beadhead. standard nymph? whatever. it should probably look like
this one, does it really need a name? does anything? that book tells you what colour the larva is, that's nice, but if in doubt, stupid bright green.
3) parachute bwos, seriously. they look
like this, that's to say they've got olive bodies and kinda blue wings.
4) dude, i don't even knwo what those are. google says they're Adams Parachutes, though.
ok, maybe i failed on less flippantly. more structured must count for something, right