Help a tech challenged human

Welp, I could never played the games before but I looooooooooved miitopia. I saw this game here and there and decided to try th demo again today! And now I can’t wait. The problem is ( th same problem I had with miitopia) that my creative brain isn’t as creative as I think and I usually just make myself and my family but in this one I want to be more. I saw a post on a site already here in the Reddit but I don’t know how to import them into the switch. The ones I created I can’t access bc I no longer have the old switch or the account so yeah ..