Introducing a bottle of breastmilk
The first time your newborn receives breastmilk in a bottle, use freshly pumped milk (frozen milk sometimes tastes slightly different). Mom should be out of the room, and preferably out of the house, because her baby can smell her presence and will be more likely to refuse the bottle.
The person offering the bottle should cradle your baby close to the chest, perhaps even skin to skin. Switch sides halfway through the feeding and burp just like mom would.
If baby fusses and doesn't seem to want the bottle, relax and don't force the situation. Your newborn will sense your stress and become even more upset. Take a break, walk and snuggle, and try again later.