When is the right time to start sleep training?

That depends. A babies brain is not ready to receive training for a number of months. The first several weeks it is important to soothe and nurture the baby around the clock so they can build a strong attachment and know that their voice (cries) matter and that they can trust a caring human will give them what they need. So, no need to make a schedule or set any timers any time soon. 

You can start doing a few basics to help your baby learn to love sleep:

• Keep it calm. No one really enjoys going to bed with someone who is super grumpy. Remember that your baby is not trying to harm you, they are just developing fast and not sure how to self soothe yet. 
• Keep it dim. Babies don't know day from night at the start. You can support their natural rhythm by keeping the lights and engagement low in during sleeping hours. 
• Cribs can be fun. If every single time you put your baby in the sleep area, you walk away-- they will grow to dislike it. Try putting them there during non-sleep hours too. You can lay them on their back and talk to them, count their toes, wave your hand slowly over their face (mesmerizing!), or just smile-- then pick them up and do something else. 
• Start a routine. When you put them down to sleep do the same thing every time. It doesn't have to be elaborate. Maybe say "goodnight to a few things in the room, read a book, sing a song, pull the shad, then it's time for sleep. 

Sleep Resources:

The Sleep Lady: https://sleeplady.com/

The No-Cry Sleep Solution https://elizabethpantley.com/

Dr. Greene Kids In the House Video

Local Sleep Consultants:

Joy McTavish http://soundbeginningsfamily.com/sleep/

Macall Gordon https://www.macallgordon.com/

Marianne Jacobsen https://pediatricsleepconsulting.com/

Jessica Mancher https://maschermassage.com/infantchild-services