Hey there, I'm a new modder and I decided to make a house, I did and it worked fine, then I wanted to add an NPC, following a tutorial online and when I loaded it it caused my game to crash so I went in to delete the NPC and I couldn't overwrite the file the mod was saved to, so I made a new one, loaded it up and there was no house, after reentering the constructioin program and loading the mod I noticed it had deleted everything in my house's interior cell and the houses exterior, so I loaded up the orignal mod and delted the NPC saved it again with another name and the same thing happened. It happened again and again and again, I don't know whats going on so does anyone have the answer

when you load an existing mod, you need to click the 'Set as Active file' button.