How much should a 12 year old boy exercise?

well if u r 14 i reccomengd not sitting on a couch all day playing games or just reading or stuff lik that so id go for a run each day or a snmall walk may be do somme pushups every morning or afternoon mabyer some sit ups im agirl and i do that and feel great all the time and am very strong now it will also get u a six pack if u do enough