Running4Beginners is a guide for adults in the UK who want to start running from scratch. Most of the articles are aimed at people over 50, though the basics apply at any age.
The site is written by a regular club runner who races a few times a year and has spent a lot of time fielding questions from friends asking whether it is too late to start. It is not. This site pulls together the reliable information so you can find it in one place.
Everything here is general information, not medical advice. If you have a health condition, speak to your GP before starting a new exercise programme.
If you are wondering where to begin, the best first step in the UK is parkrun: free, every Saturday morning, 5K, and you can walk the entire thing. No one will mind.