Start kind of small. It's difficult or impossible to be perfect so just make small changes that you can stick to just keeping in mind most of the time, like starting to avoid beverages with sugar (maybe cut out one per day at first, they are really a killer & it makes a huge difference to eventually only drink water or zero calorie beverages like coffee, tea, seltzer, etc) , or substituting one whole fruit for a snack per day, finding one healthier snack option like plain yogurt with blueberries, eating a couple more meals per week with more vegetables (i like to chop up carrots and cucumbers fresh, you can eat them with lots of dip at first, don't worry about that, get into a veggie habit then start trying for less dip)
Start with a daily or every other day short walk at the same time. Bring the family for an after dinner stroll perhaps. Little things like doing five squats every day after lunch, that's like ten seconds so no excuses... Then next week do six. Buy a water bottle and drink more water.
Little things grow into bigger things and help us transition into better habits. Ppl often try to make big changes and then fail and go right back to the same life with zero change.
You should find some sort of vigorous activity that is something you like and do that, rather than force yourself to do some sort of "program" that reminds you of P.E. class. For me, it's cycling in summer and walking in winter, plus a few dumbbell exercises.