Tell me how you put your babies down for lunch and nighttime sleep (7-…

Tell me how you put your babies down for lunch and nighttime sleep (7-8 months). How do you continue night sleep if they wake up? Our baby doesn't sleep in their crib at night. They sleep next to me because if they wake up, they search for a breast, give them a breast and fall back asleep. Is it possible to train them to sleep in the crib? Or only after I leave?