Well, they hopefully won't do what the French National Front did in the mid-1990s when they took over a couple of towns in the south of France. Within 3 months, every single municipal employee with an Arabic-sounding name had been fired. The French parliament rushed through emergency legislation in the five days between the election results (Sunday) and the swearing-in of the new officials (Friday) to remove guns from local (municipal) police in every town in the country, because there was believed to be a real possibility that the police in those two places would essentially become death squads. I'm sure nothing like that could happen in the UK, though, because nobody in Reform has ever had a racist thought in their lives.
Anyway, here's my (somewhat) tongue-in-cheek bingo card, which I look forward to filling in over the next four years (because of course I am gullible and will believe the reports in the Fake News Media™):
You can expect to see any facilities for asylum seekers in these towns either being closed, or mysteriously no longer unable to obtain council services (if they are funded by central government or charities). Ditto for funding or support of anything related to the rights of gay people or other minorities. Community events will be opened by Reform council leaders accompanied by the leaders of local churches and synagogues, but mysteriously not mosques.
The town will be twinned with somewhere in Hungary, Russia, or Florida.
Despite Reform's hatred of "woke", almost everything will be couched in ideological terms worthy of a far-left student union debating club. Any programmes that link the council to the local university will be shut down because "Everyone knows academics are all lefty Sharia-loving woke nutters".
Any remaining plaques saying that the leisure centre or library was partly funded by EU money will be chiselled out. Libraries will be inspected for "woke" content by lefty do-gooder vaccine-loving authors such as Roald Dahl.
Schools under local authority control will be required to fly the Union Jack outside and have a picture of the Queen (not the King, he's a bit flaky) in the hall at assembly.
To the extent that the council has any sort of say about policing, all of the woke namby-pamby "Community support" nonsense will be out, and the police will be put back to their traditional role of giving youngsters a clip round the ear. Needless to say, such clips will be administered on a strictly colour-blind basis.
No vegan food will be available at any official function. Nor will the buffet items have any allergy warnings, as that's all woke nonsense and nobody had allergies in my day.
Local reporters who ask too many awkward questions will find themselves no longer invited to cover council meetings. They may or may not have dog shit put through their letterboxes. The police will be too busy clipping youngsters round the ear to investigate.
I also expect that we will discover that a lot of Reform councillors have "interesting" pasts, including in quite a few cases substantial arrears on their council tax or child maintenance. I remember when the BNP won a few council seats around 2008-2010 and some of the stories were hilarious. There will be a culture clash within the Reform group between those who are actually serious about crime, and those for whom fly-tipping or drunken assault are part of a normal weekend: "You can't even slap your wife any more, it's political correctness gorn mad". (To be fair, a lot of local councillors of all parties seem to have utterly chaotic personal lives.)
In many councils the Reform group, which will turn out to be a coalition of people with very little in common apart from below-average anger management skills, will split. This will often lead to the slightly-less-barking Reform rump having to be propped up by the Tories because it's four years until the next election.
Massage parlours will become great again.