Reset the home page

Hi. I had made some changes to the home page, deleted some things, added some but I would like to restore it to the original demo design, and change the demo option from 1 to 3,but I cannot find a way to do this without resetting the whole website(I don’t want to do that). Please help.
Also, I could not find how to change the look of the store to have more columns, instead of just 1