A couple good quotes...

The Forge Tools 3 has modding documentation which is a good introduction, but some of the information is outdated and has changed for Entrenchment and Diplomacy. According to the Sins Mod Set.pdf you will need to copy the ENTIRE folder set from your SoaSE install directory to the created mod folder, then convert the files you wish to modify to text. Those which are not included will not be used by the game.

For the Entrenchment and Diplomacy expansions you only have to include the files that you want to change and if you want to "remove" an original file you have to remove it from the entity manifest (which is explained in the documentation). Also note that it includes some reference files which are outdated and you will need to create your own. Or get harpo's Reference Files

Each faction can build a max of 9 tactical, 9 logistic, 9 capitals, 9 frigates and 9 cruisers (note that frigates and cruisers are the same, but they are just shown on different places in the U.I.). You can also place tactical modules in a logistics slot and vice-versa. An entity can have a max of 3 different weapons. As far as it is known there isn't any limit on research levels. - thanks gruntmaster1 and harpo99999

All starts with the player entity file... from there, everything evolve like a tree...

The player entity links to the ship entity which links to ability entity, which links to buff... ship entity links to .mesh too, which links to texture and hardpoint, and last a link to particle effect.

So, the best thing to start is read the player entity file and from there, follow the way to what you wish to change...

In fact, the main file is somehow the galaxydef file, somehow the root of the tree... but for little edit, you don't need start there... but if you wish add militia, planet, etc, that is the starting place.   Thoumsin

Anything that starts PlanetModule has to with the planet structures, Usually ships are referred by their roles, such as Frigate(Race)(ship type), planets are labelled Planet(planet type), all abilities also have a correspond buff.

The way I learned to mod was that I take one of the mods that do work, and compare the files to the base game files, you see what has been changed from the base and see the difference in the game, also, it also helps that there is a dev.exe, make use of it, it allows you basically to change a lot of the variables in the game to make sure everything works out.   ice27828

There also [Tutorials] 3D Modeling, Texturing, Importing & Converting

 The first thing on a new modders list should be the Developer.exe's. Weather you are starting to build a new mod or testing a downloaded mod this tool is very useful for finding errors and game testing. If you are not sure about the errors generated or you want to keep track of them you will want to Enable Logging, then you can copy the information to paste into a thread in the modding forum.

Appreciatte the replies, i'm having a little fool around, who knows, if what i'm considering works I might just publicly release. What i'm aiming on doing overall is really the following;

Increased fighter/bomber presence in combat, with a couple of cruisers having the ability to deploy a single squadron while to be more representitive of its use in combat. E.g. A Kodiak being able to field a single escort squadron to make it a tad more versatile on larger fleet engagements while increasing by a balanced degree the squads deployed by mini carriers and certain Advent units who seem to specialise in them.

Reworking some of the Capital Ship abilities to be more passive based to represent base technological upgrades rather than on use CD abilities. E.g. Removing say two on use CDs on each one and placing a passive upgrade, an example I would like would be say for Long Range Capitals to have an upgrade such as Increased Range Capacity and such. Would definately be careful with balancing these however.

One of the other ideas is slightly odd but hey, if it works could be interesting. Introducing a tertiary planet defense structure which would act as a combat augment for other stationary defenses, giving range/damage/chance to hit bonuses (something along the lines of a Combat Information Centre).

Final thing would be tweaking high end upgrades to allow more fleet versatility (an example being something I was thinking might be interesting, taking the Subverters capture unit ability and offering an inferior version for the other two factions in the form of say a boarding party/mental pursuasion ability for the command frigates or such).