Need Exercise Ideas for a New Comer

Well, at age 53 with 2 tween children you would think I could figure out some exercises to do. Problem is, I don't know what to do to get started. I am an Instructional Aid for Kindergarden so I stay 'active' during the school year, but I don't do any actual exercises (and haven't for ??? years). I have Plantar's Fasciitis (heel spurs) so my feet sometimes really trouble me and limit my long walks. Can anybody help me get started on some low impact cardio and strength exercises? I am 5'5, 230 lbs., looking to drop to 150 lbs. Other than the feet, I am relatively flexible and able. Thank you for any ideas you may send my way. I don't even know the names of exercises to plug into daily planner! PLEASE HELP