Start doing the local Park run. See how fast they can get.
Do a 10k. There will be local races and running clubs which I’m sure your fiend can get involved in.
Running isn’t rocket science but all too often people do too much too soon.
The most important thing with running is consistency. That’s how you get fitter.
Run a few miles 3 times a week for 6 weeks, be sure to have at least one day off between runs.
After 6 weeks take one week completely off
Then do the same 6 weeks again but make one of the 3 runs a longer run than the other two.
I see so many people think they can run 20 miles with zero training or base fitness , they attempt it and get injured then can’t run for months.
Have fun