I haven’t been able to transfer data from old phone to new phone using quick start. Can you advise how to do this without quick start

I have recently upgraded to an I phone 15 plus from a 12. I haven’t been able to use quick start as new i phone 15 said it needed to update software first. I activated update but it just kept freezing and update didn’t work. I’ve since accessed my new phone by declining quick start without transferring all my data from old phone as was unable to get into new phone otherwise. Now I’m not being prompted to use quick start. Is there another way to do this. Thanks