When it comes to physical activity you should be mindful about your target goals for why you are doing it. Do things that you enjoy and don't give you too much stress. Is it a group or individual activity, where is it, what you need and how costly and effective is it. Not every activity you will enjoy but you should find one that meets your standards.
You should also keep in mind about health conditions, attitude, reason for participation, environment etc. Don't overwork yourself mentally nor physically and always aim for what you want out of you workout. With exercising outside make sure to be aware of the weather hazards like heat exhaustion, heat stroke, heat cramps and hyperthermia.
Caloric balance is comparing the calories you consume to the calories you burn. You burn calories two ways, one by processes that keep your body going and secondly through physical activity.Converting calories into energy is called metabolism. If you consume more calories than you burn you gain weight. If you burn more calories than consumed you lose weight. If both is balanced then weight stays the same.