I've started to notice more and more as I study the ISS, that I can only ever find pictures of one Soyuz docked. Where is the other one?

Lets say their sending up a crew of 6 for an expedition.
A Soyuz craft can only carry 3 at a time (wiki), thus meaning another one has to launch later.
(Which is why theres always a period where only 3 of the 6 are on the station)

What modules do both the Soyuz dock to?

I also feel that I might be looking at this the wrong way. Please correct me if I'm wrong that both are docked at the same time?

Also, can someone please add correct tags, I have insufficient rep and can't find any relevant ones.