When should I put my daughter in her crib...?

My daughter will be 5 weeks on Saturday. We recently learned that she is a belly sleeper. She has gas alot and although we give her gas drops or gripe water to help, it doesn't do much comfort to help her sleep. The pressure of sleeping on her belly makes a world of difference. If she's on her back she only sleeps for maybe a half hour, and on her side maybe an hour.

I want to start sleep training her so we can get on somewhat of a schedule(she's a newborn so I know schedules aren't ideal). But when should I start putting her in her crib to sleep? I am nervous because of her being a belly sleeper. I'm a FTM so I need any tips/advice I can get.

Thank you