Some types of implants, for example form-stable (gummy bear) and textured round implants, should not be massaged. Even for smooth implants, there is no real evidence that massage makes a difference in capsular contracture. Your own surgeon will have specific advice for you.
Best time to do anything is when your chosen surgeon instructs you to do massages/exercises/ wearing bras. You paid him/her to give you the best experience. We do not know you or your medical/surgical history/...
Always best to run these types of questions by your own plastic surgeon, who knows your situation best. He/she knows exactly what was done and is ultimately responsible for your care. Best wishes; hopefully you will be pleased with the outcome of the procedure performed.
You can massage the breasts whenever you like. But there really isn't any evidence that indicates that massage is effective in reducing the risk of capsular contractures. The post operative bras and garments are also something that is usually directed by your surgeon. All of us have our own suggestions, but there just isn't a whole lot of concrete evidence to suggest that any of us are right or wrong. I have my patients wear a sports bra for the first month after surgery.