Could someone tell me how to install planet dev kit for spacebuild?

I know it’s a dumb question, but how do I do it? I went browsing everywhere in my steam folder and tried, but couldn’t succeed.

Steam\steamapps\username\sourcesdk\bin\orangebox\prefabs

Thanks alot. I’ve been trying to figure it out. Also, I have a new problem, I have the svns of spacebuild 3 and lifesupport and resource distributation and all of that, but on singleplayer, I can walk out into space without any resources and nothing changes. In water I need air though? Anyone got a solution?

You have to change the gamemode. Ask in the garrysmod help section.