I've made videos on a similar topic before and spoke about how you should ease into running when you first start out, to prevent injuries. Today I wanted to talk a bit more about this and how you can build fitness even if you are slowly getting into running.
It's hard to build fitness on only a few kilometers of running a week. That's why during this transition phase I strongly recommend you use your bicycle to do most of your training.
The bike is something you can start out with and immediately do at least an hour a day of training on, because it is so low impact.
You can use the bike to build up your fitness and keep your running kilometers low initially just to get those new muscles used to the activity.