I'm having trouble understanding how exactly game mechanics work, when an investigator gets to the Other World.

During phase III, "Encounters in Arham", if player enters the gate or is drawn through one - does he/she have an OW encounter in phase IV, during the same turn? That would mean two encounters in the Other World for a common scenario (both OW areas), three or more if an investigator is delayed (and of course only one, when he or she draws a Gate Card, that says "immediately return to Arkham" / casts "Find Gate").

FAQ isn't really clear on the subject:

Q: Why is an investigator delayed when a gate opens up in their location, but not delayed if he enters the gate normally?
A: If the investigator was not delayed by a gate opening up in his location, he would be able to get through the Other World having only one Other World Encounter rather than two.

So, two OW encounters for a delayed investigator, how many for a conscious one?

winner.schnitzel said:

A conscious investigator entering and going through an OW without ever being delayed has 2 OW encounters. An investigator who gets sucked through a gate due to one appearing in an Arkham Encounters phase is delayed and has 3 OW encounters, one on the same turn he gets sucked in. The only exception to this is if the investigator has some item or ability (for example Mark's "One Man Army" that prevents him from being delayed. Btw, an investigator getting sucked into a gate due to a Mythos card still has only 2 OW encounters, because he stands up at the beggining of the next turn.

I hope it's clear now!

winner.schnitzel said:

I will add a litle to what Tox has already said.

Yes, you can have an Arkham Encounter and an Other World encounter in the same turn.

Simply resolve each phase in turn.

1. Upkeep

2. Movement

3. Arkham Encounters

4. Other World Encounters

5. Mythos

Each phase is completely separate and independant.