Loosing weight starts with your diet. As the saying goes, you can't outrun a bad diet.
In my opinion loosing weight is 70% diet, 20% working out and 10% mental will.
If just looking for loosing weight, cardio is your go to. You could start with with just walks to reduce strain to your joints and build the first muscles and stamina for more.
There's also workout programs like 30 Days of Cardio available in three flavors, light, regular and hard:
30 Days of Cardio Light is a no-equipment low-impact at-home cardio-oriented program designed to get your body moving, your blood flowing, and your heart rate up. It’s perfect for anyone looking to...
darebee.com
If looking for a more holistic approach that kinda addresses everything, there are programs like:
Baseline
The Baseline program is a starter program for anyone who is just beginning their fitness journey or is coming back to fitness after a long period of time. It’s designed to get you moving and prime...
darebee.com
or
Foundation (Light)
The Foundation Light is a low impact 100% bodyweight based fitness program perfect for anyone with joint issues, recovering from an injury or is heavily overweight. It is also perfect as bodyweight...
darebee.com