How to make add‑ons for Sandbox (gmod game)

(Maybe I’m blind and I can’t see the thread about this)

I want to start making certain content for the Sandbox game (Garry’s Mod Game ) so that it appears in the spawn menu. 

 How is this done?

https://sbox.game/f/gendev/943/1/

Someone mentioned that addon publishing is broken, I’m not entirely sure. But I think the system will soon be rewritten to use the Steam Workshop, so that addons load when the game starts.

So, they’ll make a system like in GMod, and you’ll be able to subscribe?

If that’s the case, it’ll be OP, because it often turns into a mess of random mods.

For example, if there was something like LVS or ARC9, the overall add‑on network would be a mess of random stuff.

Addon publishing isn't broken. I just updated my yesterday.