For a newborn (0–3 months), we recommend the baby wrap as a first choice: the custom-fit position it provides best respects physiology, promotes digestion (fewer colic episodes and reflux), regulates temperature, and stimulates bonding through skin-to-skin contact. It also extends the feeling of security from the womb — no small thing in the first few weeks.
If knots intimidate you, the sling is an excellent alternative: same benefits, quick to put on. A structured baby carrier is perfectly suitable too, but won't offer the same feeling as a wrap :)