Retired now so taking this seriously at 65. I need exercises and to how much should I run?

Start s rlowly. If you are starting from scratch, start slowly and build slowly. Your body needs time to adapt. A mix of aerobic and resistance makes sense. Additional exercises like yoga and pilates are beneficial. The best way to start running is with 20 min of run/walking. Add segments of running for 1 min and walk for 4. Slowly bump to 2 run/3 walk until you can run 20 min solid. This should take 6-8 weeks.