My 12-week-old fights naps and barely sleeps 10 hours a day. when i put him down he screams. help!?

Find a good routine: For a normal, healthy baby 3 months of age (13 weeks) is about the time when he should be able to learn sleep habits. After each feeding/burping/diaper change, a parent can do a little playtime, then a little quiet bonding, then lightly swaddle the baby, put him in the crib, turn on the musical mobile, and walk away. If unsuccessful, parents can talk with the doctor at the baby's 3-month check-up.

Still adapting: Some would call the first 3 months a 'fourth trimester' for babies, still trying to adapt to outside of mama. They feel best when feeling like inside your belly. So held or wrapped feels best and put down feela worst. For now continue to work baby to sleep as best you can. Average is 12-15 hours but for some its 10-11 hours. I favor the 'cry it out routine' but only well after 4 months.