It’s been a while since I’ve used Roblox Studio. I remember there being an option to change the starting place, but it’s not where it was before. I have a studio file in my PC and I want it to be the secondary place, not the starting place, and create a new starting place. So how do I do that?
Create another place called Secondary Place inside your universe (right click the Places area and click add new place), and then open your studio file, and Publish to Roblox As… then you will select to overwrite this Secondary Place with your file. Once this is done, you can do the same to overwrite the starting place with a new file.