JSGME is a tool to let you easily and safely enable and disable mods
Download here
http://www.users.on.net/~jscones/software/products-jsgme.html
Here is a step by step guide to enabling a mod via JSGME.
It is written as if you are enabling TMO, but the steps are the same whatever mod you are enabling.
http://forums.ubi.com/eve/forums/a/t...5/m/5181035206
There are several major mods that change pretty much every aspect of the game.
TMO - Trigger Maru Overhauled
RFB - Real Fleet Boat
FOTRS - Fall of the Rising Sun
These 3 are for US Fleetboat operations in the Pacific
OM - Operation Monsun
This is for U-Boat action in the Atlantic
You will probably want to get the basics down first before jumping in to a major mod like one of the above.
But you will probably see the above acronyms bandied around on the forums so I thought it would be helpful if I mentioned them.
I wouldn't worry too much about the AA tutorial.
Standard procedure when an aircraft turns up is to dive.
If you try to duke it out with an aircraft in any of the major mods, you are in for a world of hurt

This is realistic.
Submarines v's aircraft - there was usually only one winner, and it wasn't the sub.
There's a steep learning curve at first, but stick with it.
SH3 and 4 are the only games I have that I continually come back to.
They're very addictive.
Continue reading any guides you may find on the forums.
Ask any questions you want - you're right, this is a friendly and helpful place.
Welcome aboard and good luck Skipper