I will be short about exercise because it deserves a separate and extensive discussion.
In few words, exercise is extremely important for our health in general. 10 000 steps a day as advocated by various authorities sounds like a reasonable approach. I recommend at least an equivalent of fast 40 minutes walk 5 times a week. I do believe simply leisurely walked 10 000 steps are not necessarily sufficient, it should be at least some element of exertion with heart rate reaching aerobic heart rate zone. Click this link to estimate your aerobic heart rate zone, but targeting heart rate just above 100 is a reasonable approach.
Important moments about exercise and weight loss is to understand that exercise alone without proper nutrition may not result in any weight loss at all and in fact may even result even in a weight gain. Why? Because it is very difficult to burn significant amount of calories and very easy overindulge on food after reasonable exercise without any guilt.
As an example, an average size adult will burn around 70 calories an hour during "household" walking, or 170 calories per hour of "pleasure" walk, and may be as much as 400 calories per hour with backpacking. Let's say walking faster than pleasure and with motivation may burn around 250 calories an hour. 2 hours will create the ideal 500 calories deficit. How much is 500 calories? 4 spoons of healthy olive oil. One commercial tuna sandwich. 4 big size apples. Less than 100 grams of nuts.
At the end for most people it is much easier to skip some food rather than to get involved in significant exercise.
If you are serious about real exercise then it is a different story, but then this web site is not necessarily addresses the questions that real athletes and body builders have about their nutrition, their priorities are completely different.