Good on you for wanting to make a life change; everyone on here has there own story for commencing running.
Firstly have you visited your medical professional to ensure it is safe to start?
Secondly, put a sign in a prominent position “I am going to run a 5k”
A couple of hints; Start easy, possibly completing the first level twice. I don’t like calling the program by weeks as mentally it makes it rigid; I prefer to move level when I’m ready.
Don’t get caught up In the distance aspect early on. Some push through the walking rest periods to the detriment of the efforts. Interval training is about completing each repetition at a specific rate (C25K is easy / conversation) then resting enough in the walking phase so you are 100% ready for the next reputation.
Everyday that you do something exercise related adds to your long term fitness
The None to Run is a good alternative as it has less large jumps between levels and body weight trading is included.
https://veraviafit.com/wp-content/uploads/2018/11/N2RPlan-3-1.pdf
The UK NHS webpage to the C25K also has a body weight program linked.
YouTube James Dunne has a lot of information about running basics and injury prevention.
https://www.youtube.com/channel/UCEBjuHm_Z6hz8Q6C_dm8bSg
If you want to stay inside there is a YouTube site with all the C25K runs with a timer;
https://www.youtube.com/playlist?list=PLAqmiKkEjoSrrdiPBP3jBfgRAgz9T5QWJ
There is nothing wrong if your knees or ankles hurt in completing a C25K run on an elliptical.
Be the physical person you want to be.
Best of luck