The values are multiplicative, so because of the commutative property, you get the same value regardless of which one is done first. The order makes no difference when you multiply the values.
This big part determines the Pokemon's stat before it even enters the battle. This is the (Base Speed+252 Speed EVs) part you have here, though the whole thing is collectively one number being multiplied.
From there, you just multiply by anything else like stat boosts/drops, items, abilities, etc.