You should start to implement time out around the age 18 months to 2 years.
Assign time out chair and mat, preferably in a common area of the house, may ne kitchen area. Set rules in the house before so the child wil be aware. Be consistent; the same behavior do the same response. Count to three before you put in time out. And remember: do time out according to the age: 2 years: 2 minutes, 3 years.