SIMS 4: Starting a new game is an absolute nightmare

Did you click on the plus sign in the upper right corner of the main menu ? That's where you start a new game and this should not have anything you've previsouly played.

Yes, I do. When I create the new household, I'm asked if I want to merge or replace the household. I choose to replace. Then, When I go to choose a house, the old household is in the game!!! I start the game, then remove the old household by editing the world, but then the old sim is still inside the game!!!

i am having a problem starting a new game also, when i click the plus sign and try to start fresh, the old timeline and furniture from my previous game is still there. like it doesnt start me at sunday and the houses i altered previously are still there... its really annoying. 

I need help too. I was playing a household (Asylum Challenge) but I want to play with another household but I want them in a different save. What do I do? Because the first time I did that, I pressed "New Game" and I can't play with my old sims anymore. Please tell me what to do.

In this case, you need to press "new household" next to the play button and therefore you will be able play both sims, but live in separate homes.

YOU IS ME SAVIOR