ID:This is what each point will be referenced in. This will be important in the .variant file and will come up when you set up the variant. Name well, and make sure there are no two same names unless you want a headache later.
Location: Pretty much the same fanfare as marking the centre of the ship as before.
Angle: This control where the default gun will face. This may go over 360 degrees. I have no idea what going over 360 degrees actually does differently then if you set it below.
Arc: This determines how much the weapons in the mount can swing. Again, no idea what will be different if you set it over 360.
Turret/hardpoint/hidden: Turret is self explanatory. Hardpoint makes the weapon not spin I think. Hidden makes whatever weapon you put there hidden. Good for under turrets and fighters.
Small/Medium/Large: This controls which weapons can be mounted.
Ballistic/Energy/Missile/Launch Bay/Universal/System/Decorative/Built_In: Pretty self explanatory. Note that i am not completely sure how to use System. For those searching for how to put more flight decks I put some tags here: Flight deck, more hangars, carrier launch pad, repai/refit, fighters, bombers. note: When adding a flight deck you have to insert multiple coordinates. Or else, when fighters dock, the game will crash.