Samsung SGH-E635OKATMB - Manual (Page 11)

Section 1: Getting Started 7
Activating Your Phone
Section 1
3. Slide the SIM card into the SIM card socket so that the
card locks into place. Make sure the gold contacts of the
card face into the phone.
Note: When you need to remove the SIM card, slide it, as shown, and
take it out of the socket.
4. Place the battery so that the tabs on the end align with
the slots at the bottom of the phone.