How to easily put 4 month old to sleep?

Sa

I need help! I have always had to rock my baby to sleep for close to half an hr, Everytime she is sleepy, be it naps or nighttime. I am so tired of it being this way. How did you guys put your babies to sleep at this age? Did you have to rock them or other means of helping them fall asleep, or you had them trained to fall asleep on their own? Is it even possible to train at 4 months?

Another issue I have is my baby wakes up as soon as I put her in her crib or anywhere else from my arms, and starts crying because I tried putting her down. I have no idea what to do anymore. At night she doesn't sleep unless she is snuggled close to me. I just want my husband to be able to sleep in our bed again! 😔