Just look up abs workout but the most important thing by far is probably stay consistent

Maintain low body fat, strong core. Proficiency in bodyweight workouts (pushups, pullups, crunches, etc) is more than enough just to 'get' abs.

>>34916532
>>34916650
Crunches is the core one here. Core exercises are good, but you need to specifically work abs in order to get abs. Crunches are going to be one of the best exercises for that