In differs by city state. In general, they would all be given basic weapons training and tactics, such as Phalanx for those of Phillip II and Alexander.

In Sparta, they would start training at 7. From this age they would begin training in physical skills, mental and tactics skills and spiritual training. They would often spar one another to hone battle skills.

There isn't much sources I could find on training elsewhere. You could assume they got battle tactics and weapons training, but little more.