Slitherine

Read the guide here but found no answer to that question.

I wanted to add a deck to the Human fighter.

First I added a .png to the SHIPS/TOP folder.
So that I have there a N60_0.png and a N60_1.png.

Then I opened the ShipsBody.all file with notepad++ and changed :
Decks 1
Img "Ships/Top/n60_1.png" BIG

to :
Decks 2
Img "Ships/Top/n60_0.png" BIG
Img "Ships/Top/n60_1.png" BIG

After that I created a bat file with "PolarisSector.exe -design" in it and run it.

Problem was that when I used shift+6 to get to the human ships and clicked at the Figtherclass I saw only 1 Deck.
So how could I add the second deck?
crtl+r crtl+c crtl+v C S O H shift+number --- does not add a Deck.

I found it!

Missing step was :

Delete the .cli and .clr fighter file before running PolarisSector.exe -design
The Design editor will then use the changes that I made in the ShipsBody.all file to create a new .cli and .clr
Have now a fighter with 2 decks

Yes, you were loading the cells from the originals. But one recomendation if you did not make it. Do not overwrite the original files, you should add them as a mod in a different folder.