Exercise question: When should i exercise, before or after supper?

My 2 options are before supper (right after school) or after supper (2 hours after or something) Which would be best though? i’ve tried to look it up, but I get 2 sorts of answers. Some sources say that exercising before supper helps lose weight and keeps your appetite down, but some say to exercise after supper since you have something to burn. Which would be best for losing weight?

Another question: How does running hurt your joints? and so then how much running should i do a day to be safe? Is jogging safer than running?