@arielesse you can have as many households as you want effectively. You could pick any household that already exists and edit them or add to it too. I'm on console and there is a recommended limit of about 150 Sims I think, but it's a while since I've played on PC so I don't remember if there is a limit on the number of Sims on that platform.
So, you won't lose your household but if you don't want changes to them after you move to your next household you'll need to go into your Game Options and Disable Neighborhood Stories. So that means they won't have storylines out of your control after you move on from them. Otherwise there will be births, deaths, marriages, etc. I also go into Game Options and take off ageing. So my Sims don't age up automatically, that's a personal choice though it depends if you want them to age and die or not. What I like to do is create all my Households the way I want them and try and keep them that way. You might want them to age, that's up to you.
You can also use Other Households to edit townies/NPC Sims. If you want to make space in My Households you can also move some of your sims over to that category. I do that when My Households gets too full.
I often create a large household of family members then in Manage Households I split them into separate households. I don't always move them into a lot, that's fine they still exist without a house. You'll find them in My Households and without a house it will show them as Currently not in World. Sometimes I build them a house later. But it gives Sims relationships at the start. You can add family members at any time, so I often play a Sim for a while and when I'm ready to move on I create a relative or friend/partner then move them into their own lot to play next. My previous household isn't affected and it's easy for them to stay in touch. I've had one family spread across several worlds this way with kids, grandkids, aunts, uncles and in laws. You will find that Sims, including your creations will call your played Sim and ask about life decisions like whether to meet someone or have a baby so in effect you still get to decide on changes to their life.
Your Worlds are in Manage Worlds. Depending on which Expansion/Game packs you own. You can travel to them via your Sims mobile phone or you can build in any of them too via Manage Worlds. So you start with base worlds Willow Creek, Oasis Springs and Newcrest. I think the first world I added was Magnolia Promenade with the Get to Work pack but it was quite small so I added Get Together and got the beautiful Windenburg. Now I have most of the packs and worlds and the most recent one I added was Tartosa which is stunning and that's where my current Sim lives. You can play any lot, edit public lots do anything you want really as long as it's within the boundary of a chosen lot. You can demolish the Blue Velvet bar if you want too, you can add a park wherever you want to. It's your choice.
If you want to know anything about anything just ask! No matter how small. You'll find we're a helpful bunch.
Thank you! I’m going to look up those videos and see^^
