Can someone explain what it even means to seize the means of production?

Like if the means of production is land, and you are seizing land, sure that makes sense to me.

But most goods are not made by land alone but by machines and factories and transport systems and etc. If you seize those as preexisting entities, what happens after you seize them? If you as a group can operate and expand those things, can’t you just build them yourselves also, and if so there is a way to work within the existing framework to do that, which is to start a company. Is seizing the means of production not equivalent to starting a company and stealing things others have built for the company to get started with? Why is that a good thing?

Like I personally agree that wealth accumulation is bad if it has political power go along with it, and there are huge problems with our system and lots of debt formats should be made illegal, I just don’t get why anyone thinks “seize the means of production” is the answer and I feel like I might be confused about what that really means.