The UK electorate voted out. How it happens is not important.
By a small margin, the English electorate voted for UK to leave EU (though that of its capital and most larger cities did not).
By an even smaller one, the Welsh ditto did likewise.
The Northern Ireland electorate voted by a small margin to remain.
The Scottish ditto voted by the largest majority of the four to remain.
"How it happens is not important"? Nonsense! One might as well claim that how UK became a member of EEC (as then it was) was "not important"! "How it happens" - if indeed it does - is vitally important for almost everyone in UK and EU.
It's widely known that, when the undemocratic and wholly unnecessary public opinion poll was held, the UK electorate was woefully ill-informed about the ramifications of leaving or remaining and was asked just one absurdly simplistic question - in or out - as though anything that would affect the future of UK and EU for generations could be reduced to that! It cannot be; it never will be.
Were it indeed that simple, it would have required just a couple of signatures on a newly drafted agreement instead of almost four years of varied and immeasurably complex negotiations that are by no means complete and which have incurred immense costs for UK; see
https://www.businessinsider.com/brexit-will-cost-uk-more-than-total-payments-to-eu-2020-1?r=US&IR=Thttps://brexit.hypotheses.org/files/2017/01/Budget-et-contrib.pdfhttps://www.instituteforgovernment.org.uk/summary-costing-brexit (well out of date now but still a useful indicator)
https://www.theweek.co.uk/93785/how-much-money-has-brexit-cost-the-ukhttps://www.bbc.co.uk/news/business-46338585https://www.statista.com/chart/20544/forecast-cost-of-brexit-compared-to-the-uks-eu-budget-contributions/Note that none of the above has been sourced from your journalistic bête noire,
The Guardian.
Note also that no reference to the leaving costs was included in the public opinion poll question or accompanying documentation when voting took place; UK's electorate therefore had no idea about that aspect of the issue. This, however, is perhaps not entirely unsurprising, since the government that launched that crazily undemocratic exercise was convinced that the vote would go the other way and it would not then matter!
The only scenario in which "how it happens" could even get close to unimportance would be one in which UK were to
a) sever
all connections with EU - trading, political, cultural, security, educational, fiscal/economic/monetary and the rest
b) deport forthwith all EU citizens resident in UK and
c) bar all future travel from EU to UK and vice versa, especially immigration / emigration.
That, as doubtless even you will have noticed, is mercifully not going to happen in any form of Brexit should it ever come to pass.
Best,
Alistair