If you start running, run one day, rest one day, if you're not sore, run again, rest again. The following week if you're not too sore you could try running on consecutive days.
When you work work out your muscles get tiny little tears in them. These tears need to heal. The muscles will then get bigger. You should eat protein (meat) and drink water.
People who are used to running can run three marathons in three days and not be that sore afterwards but they didn't start there, they worked up to it.
If if you have any questions, advice or would like to share your experience, feel free to comment on the post.