Good tip, stretch afterward a lot so you stay flexible and don't get runners knee. Also, if you are "supposed" to be at the next week but can't do it yet, get there a little bit slower than the "recommendation" so you don't get shin splints. Don't push yourself too fast.

Stretch before and after a run. Make sure to stretch your whole body, not just your legs.

go slow and take small strides but lots of them.

I found from the first time I did this program that if I couldn't do the assigned intervals to just slow my pace. At first I was a bit discouraged but really it's about endurance. Speed work can come later!

I didn't run at all when I started. The first time I tried to start I couldn't even manage the one minute intervals, and the next few days my shins felt like someone had taken an axe to them. I modified the programme to make it even easier (can't remember exactly but I think I started off by running 30 seconds and walking 4 and a half minutes for 20 minutes, then I VERY gradually increased the length of the jogs (by like 2 or 3 seconds per week) and shortened the walk breaks until I was ready to start week 1 again.
The first time round I did the entire programme on a treadmill, which I found easier on my shins and knees. Decent shoes are extremely important, as are stretching and making yourself run a lot slower than you think you need to. Someone on here told me to run at a pace that allowed me to sing under my breath.
Have faith in the programme, listen to your body (not your mind though, that will protest and scream and tantrum on you until you learn to ignore it or drown it out with music) and don't be afraid to repeat weeks occasionally or adapt them to suit you.