Denver GSP-131 User Manual page 2

Insert the SIM card: The SIM card contains your phone number,
PIN code, links to operatorservices, contacts and
SMSmessages. To access the compartment containing the SIM
slot, turn off the phone and lift up the cover starting from the slit
on the bottom right corner. Remove the battery. Insert the SIM
card into the slot with the gold contacts facing down.
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