If you're unfamiliar with wildfires/bushfires, please seek out information from local emergency services on what to do, if and when to leave and what to take.
Here's some info on preparation, albeit Victoria, Australia specific, but much of it can be generalised.
There's a printable pdf for planning.
In the most recent 2019-20 "black summer" bushfires, 33 people were directly killed and billions of wildlife estimated to be killed.
24 million hectares (240,000 sq km) were burnt.
The area of the UK is 244,000 sq km for comparison.
(If you're gonna try to fight fires yourselves, you really shouldn't unless you have the training and equipment. But if you do, don't do it in shorts and a t-shirt - they won't protect you from embers or radiant heat - radiant heat kills)
https://www.cfa.vic.gov.au/plan-prepare/before-and-during-a-fire/your-bushfire-plan