Adding SIP trunk

hi i have a voip provider given ne this sip configuration for my asterisk dialer
how do i set this up on my asterisk server.?

[grnvoip]
allow=all
canreinvite=no
context=from-trunk
fromdomain=99001315.grnvoip.com
host=99001315.grnvoip.com
outboundproxy=70.42.72.140
insecure=very
type=peer

on extensions.conf:

[from-trunk]
exten => _Z.,1,Dial(SIP/70.42.72.140/9900131501${EXTEN})

how am i going to add this up on the extensions.conf