How can I get my baby to fall asleep?

Create a tired place. Babies do not understand or desire sleep like an adult. They drift off like you would in a boring lecture. In the womb the norm was sound (hesrtbeats) and comfort. You need to create a comfortable "tired place" where baby can go to settle and drift off, day or night. Try to use the same area for day & night naps. A fan buffeting in the background helps. Subdued light helps. Avoid direct stimulation.
Routines. Initially, babies may have chaotic schedules, with night and day switched. Over a month or so that fixes itself with daylight exposure. Best thing to do is establish a bedtime routine. Mine involved feeding, a brief amount of play, bath, change, book, feed, bed. Always put them down awake, so they recognize the crib as the sleep place. If done consistently, they will fall asleep on their own.