Hi Lina. You should look for a course that has a mixture of hills/stairs and flat ground to get the most from your running. If you aren't used to it, stick to your walking track and jog for as long as you can. Once you think you have done as much as you can, walk until your breathing and heart rate have slowed down a bit, and then start running again. Keep doing this until you can almost run the 5ks. Once you have achieved this, find a longer run!
Beware of getting into a rut like most runners do. Most hit a plateau because they don't mix up their training (ie exercise other than running), and run the same course at the same intensity. You need to keep challenging yourself if you want to keep building your fitness.
It is also a good idea to make sure that you do weights and interval training if you want to improve your ability to run distances. Your glutes are really important for propelling you up those hills! And running can be tough on your knees, ankles and back, so make sure you have rest days. Stretching your legs will also be important, as regular runners tend to have tight hamstrings which can cause you all sorts of problems.
Goodluck!
