how is ARC turning every source into a named graph

[Flyon]

it sais here: http://markmail.org/message/6ukhffyec4tdgtox that "any
source is turned into a named graph in ARC"

Could you help me understand how that works?

If I want to create this statement:

((( x of y) as z ) in q )

in quadruples:
[id = subject - predicate -object]
a = x - of - y
b = a - as - z
c = b - in - q

I'm I correct to think that I need to do this with separate queries,
so something like this:

INSERT INTO <a> {
x of y
}

INSERT INTO <b> {
a as z
}

...

Or is there a better way to do this?