The Couch to 5K (C25K) is a beginners running plan created by Josh Clark in 1996 for those aiming for a 5k in about 9 weeks. You will be running 20 to 30 minutes, three days a week. The daily workouts start with a 3-5min warm-up walk and works up to running three miles / 5k initially alternating with walking, then without. It progresses slowly so most people can manage it; if you are willing to train ay least 3 times per week.

This is the summary from Josh Clark himself:
"It all starts with being gentle to yourself. The first week of Couch to 5K asks you to jog for just a minute at a time, an achievable victory for most of us right out of the gate. The challenges gradually increase, but in increments that are always within reach. In the process, one discovers that there’s more inside them than they realized.

Nearly all of us can run if we want to; we just have to start by walking or jogging. Speed, distance, frequency—those are all beside the point. The animating notion behind Couch to 5K is that anyone who laces up their shoes and gets moving earns the right to be called “runner”—and to enjoy the benefits in mind, body, and even self-image of finishing a run or crossing a finish line. Recognizing yourself as a runner—giving yourself permission to do this thing—is half the trick of actually doing it."

LINKS
https://bigmedium.com/ideas/bbc-how-josh-clark-invented-couch-to-5k.html

TIPS
You can move any days/days-off to any other day
Where a session has multiple activities (intervals) go easy at first but try and finish strong
Initially run for time but at the end you can run against a set distance
By all means run in a group but try and stick with your pace and plan
Keep in mind you will improve if you slowly do more each week
Don't worry if you don't hit the target every time, if necessary you can repeat it

THIS PLAN IS BASED ON EFFORT (RPE)
We applied the 1-10 effort scale so you know how hard to go (aka RPE / Borg scale)

Level 1: Like I I'm watching TV
Level 2: I'm comfortable and could maintain this pace all day long
Level 3: I'm still comfortable, but am breathing a bit harder
Level 4: I'm sweating a little, but feel good and can carry on a conversation effortlessly
Level 5: I'm just above comfortable, am sweating more and can still talk easily
Level 6: I can still talk, but am slightly breathless
Level 7: I can still talk, but I don't really want to. I'm sweating
Level 8: I can only keep this pace for a short time period
Level 9: This is too hard, I need to stop any second
Level 10: This is impossibly hard