Can Someone Explain the Surprise Round to Me?

[Mindfever]

The Surprise Round states:

If some but not all of the combatants are aware of their opponents, a surprise round happens before regular rounds begin. In initiative order (highest to lowest), combatants who started the battle aware of their opponents each take a standard or move action during the surprise round. You can also take free actions during the surprise round. If no one or everyone is surprised, no surprise round occurs.

So what I am wondering is if the Surprise Round is a specific window of combat?

The way it looks combat has three windows

Initiative: Roll to see who goes first

Surprise Round: Determine which creatures, if any, are aware of the others and if all are surprised or none are that window is skipped.

Combat: In initiative order players and NPCs take actions until combat is resolved

Also what happens if there is someone who always acts in the surprise round? For instance a Divination Wizard.

[Ragoz]

You have it exactly right.

As for always acting in the surprise round they will act regardless of being aware but there still has to be a surprise round. For that to happen there must still be someone who is aware and someone who is unaware.

[Murdock Mudeater]

Mindfever wrote:

Initiative: Roll to see who goes first

Surprise Round: Determine which creatures, if any, are aware of the others and if all are surprised or none are that window is skipped.

Combat: In initiative order players and NPCs take actions until combat is resolved

Also what happens if there is someone who always acts in the surprise round? For instance a Divination Wizard.

Surprise round is really two steps:

You determine awarness. Awareness is about being aware of the attack and of the enemies. This could be Hiding enemies, but it could also be enemies disguised as allies. This really should be considered it's own step.

Then if some creatures are aware, but others aren't, those that are aware perform an action (Move OR standard) in the surprise round. This is handled in initiative order of those that can act. So if a character always acts in the surprise round, they still may act after other characters if they roll poorly on the intiative check.