Adding amp/speakers to existing setup

[Surgical_ass]

Trying to get my ducks in a row b4 I pull the trigger on tower speakers. This is my first install of any type of audio equipment.

1. The boat was NOT "prewired for tower speakers with amp" I will be trying to figure out what wires do what in the tower. I have found two quick connect looking devices behind the observer's seat port side. I'm assuming these are for connection to the amp I will be adding? Any ideas on which color wires I should be looking for in the tower to connect speakers to?

2. When adding the amp I will need a fuse between the amp and battery on the hot side correct? Where will the wire from the amp to the head unit plug in at the head unit? I have a USB looking connection under the helm is this it?

3. Will it automatically pull up as zone 2 when I plug into the head unit or will something need to be done?

4. I like the ease of setting the gain on the kicker amp but I have heard that wetsound amps dont need to be set. Is this correct? Also is there an amp that can accomadate 6 incabin speakers a sub and 2 towers without sacrificing quality of a 2 amp setup? What is the amp that's reccomended for this?

I'm sure more questions will come up but this is all I can think of now. Thanks!