The Couch to 5k programme can be downloaded as an app of you have a smartphone.
Otherwise you can Google it as has been mentioned.
I'm a regular runner, nothing hardcore, 5miles is my top mileage if I feel in the mood as I get bored by about 3 miles usually as I run alone due to lack of running buddies.
I did initially run when I was around 18st and ended up with a damaged knee, it still troubles me now.
I have bought myself a Nike Victory sports bra which pulls on over the top like a crop top and I think it is excellent. If I ran in a normal bra it actually hurt. I am a DD.
It would also be a good idea to get yourself sorted with some semi decent trainers if you decide you like it, this helps protect your knees and other joints from stress.
If you go into a running shop, most will check your gait out for free with no obligation to buy, you can then take this information to a Sports Direct or similar where the trainers are labelled as to which foot type they suit and try a few pairs on.
I spend £50 max on trainers and they are so much better than going in your normal sobbing around ones.
Good luck.