Genuine question. How would a transition to socialism work in practice?

Eating the billionaires and “nationalizing” publicly traded companies is the easy part. Saying “you can still possess your car” is also easy. The hard, and ultimately unpopular, part is everything else in between. Summer cottage? Family farm? What happens to pensions/retirement savings, land ownership, inheritance, small businesses, the apartment your are renting out to pay for your own rent…

Yeah, I know, these things tend to be out of reach for younger folks these days, precisely because of hyper wealth concentration. So with billionaires and mega corps out of the picture, the question still stands.