>>1998310cont.
regarding the anti rotation washers importance see picrel. The gear hubs axle has two flats on either side. Those flats are located by the flats in the hole of the anti rotation washer. The position of those flats in relation to the tang of the washer then dictates how the assembly sits in your bike, relative to horizontal. Notice how every of those washers orients those features at different angles to each other.
On a side note: Remove your rear wheel and measure distance between the inner surfaces of your rear dropouts. This spacing, also called 'over locknut distance' dictates what hubs you can run. You can usually get away with squeezing things to fit but its best to just have things that are compatible to begin with. Also aluminum bimes might just fail spectacularly if you do really stupid stuff like putting a way too narrow or wide hub in.
