Totally agree with ShowofHands - you don't start running by running!
Do 1 minute walk, 1 minute quick walk (or a jog if you're up to it), repeat that 10 times and you've done 20 mins on your feet, and doing exercise. Do this 3 times in the first week.
Then do one min walk, 2 min jog, and again for another 6 times and again, that's a further 21 mins a day exercise - repeat three times. And with this one, your breathing will be easier and you'll get fitter more quickly than if you just try to run / jog straight away.
3rd week you could try 2 min walk, 2 min jog - repeat for 6 repetitions and you've run and walked for 24 minutes - so this way you're increasing your time on your feet, distance and ability to run. Again repeat this again twice more in that week.
4th week - try walk 1 min, run 3 mins - do this 6 times and you'll find it harder initally but this works out at again 24 minute work out - but more running!
5th week - try 2 min walk, 3 min run, 1 min sprint - do this one 5 times and you're up to 30 mins exercise and probably doing about 2 miles!!!
So by the end of the 5th week, you could be running / exercising for 30 mins and doing nearly 2 miles - repat this 3 times in week 5 and you're running / exercising 6 miles in one week!
Then week 6 - 1 min walk, 3 min run, 1 min sprint - repeat 7 times in total and you're up to 35 minutes.
Week 7 - 1 min walk, 4 min run, 1 min sprint - do this 6 times and that's 36 minutes in total.
Week 8 - 1 min walk, 5 min run, 1 min sprint - repeat 5 times and that's 35 mins and probably 3 miles? So repeated 3 times in one week and you're up to 9 miles running / exercise in one week!!! In only 8 weeks...who'd have thought it?
Week 9 - 1 min walk, 6 min run, 1 min sprint - repeat 5 times and that's 40 mins exercise.
I know this works as I've done it.
Not easy to start with but does build easily - you can physically see the imporvements very quickly and in 3 months, you could be up to 10-12 miles running per week.
The sprinting (fartlek sprints) helps increase your cardio capability (so you can run more and recover more quickly) whilst the increase in time on your feet helps your skeleton get used to what you're asking it to do. If possible, run on soft ground in the park (around the football pitches) as it's easier on your joints.
Good luck!