Where and how do you remove the the SIM card from your phone and change it in another?

i need to know this so i cant reativate my new phone i just got from a friend, it is already used so i need to change the number aswell.Where and how do you remove the the SIM card from your phone and change it in another?Most Sim Cards are located under the battery inside the phone. Once you swap the sim card over to the new phone, (which needs to have a sim card slot as well), the number registered to that sim card along with whatever phonebook contacts are stored will transfer to the new phone.
Where and how do you remove the the SIM card from your phone and change it in another?
Open up the back and take out the battery. The SIM Card should be in a little compartment behind it.