A baby's sleep is very different from an adults; it is important because it allows him/her to grow! A baby's sleep cycles are about 50 minutes during which restful and agitated sleep alternates. During the first few weeks, a baby will find it hard to find his/her rhythm. Thereafter, depending on age, a baby will need more or less sleep:
In addition to night sleep, a baby needs a nap to rest. Up to 6 months, 3 naps are often needed: one at the end of the morning and two in the afternoon. Then, up to the age of 1, the last nap of the day can be stopped.
A calm and reassuring environment is ideal for a baby with not too much light but not completely dark. Don't be impatient, a baby needs more time than us to go to sleep!