You can go to a trade school teaching carpentry and get a certificate making you eligible for some jobs in the field. You can even try your luck by being a carpenter's helper, doing unskilled work. But if you really want to be an all-around carpenter, who can perform any skilled task he or she is asked to perform, you had better get the broad experience you can only get by completing the 8,000 hours of work experience required to graduate as a journeyman carpenter.