I have everything correct I think, and the game loads fine. But when I open ship design, none of my new modules show up. I have an install file present.
One thought I have had is that something may need to go in the ‘mods’ folder in documents/mygames/gratuitousspacebattles2 
Yup, you need to stick a file inside /data/installs like this:
[config]
name = testdlc
path = testdlc
guiname = TEST DLC
author = Positech Games
description = This is a positech installed piece of DLC.
texture = testdlc.dds
enabled = 0
Or you can create a folder under /my documents/my games/gratuitousspacebattles2/mods
If you have subscribed to any steam workshop ships, you will already see a bunch of folders in there…I should write a guide about this… TBH I thought I already had, but clearly not 
Hmmm…
…I put an install file in pathing to the folder in the mygames/gratuitousspacebattles2/mods, inside the mod folder I put data, inside that I put modules, inside that I put the modules file, then I put a languages folder in data, and put a modules_text in there.
Now it won’t even open properly ;-;
Hi, if you use that folder, I don’t think you need the data folder.
Here is a complete guide:
http://www.gratuitousspacebattles2.com/modding_packaging_a_mod.html
Okay, so I basically changed the path in the gsb2_base file to ‘voidcollective’, put a file in mods called voidcollective, and stuck ‘languages’ and ‘modules’ in there. I then changed the author, the name, the guiname, and saved as a new file. It still won’t open ;-;
Hmmm… can you email me all the relevant files and I shall investigate (cliff AT positech dot co dot uk)
I have emailed the files.
I replied to you, but yeah… I screwed up… A fix in the next patch will make loading in ship module spreadsheets actually work properly