about site to site VPN....

Dear Sir :

our office using fortigate 60 and sonicwall pro 3060 ,
i have found this article

http://kc.forticare.com/default.asp?id=1657&SID=&Lang=1

but i can build up a VPN connection,
i need  to know ,

To add the addresses
====
Go to Firewall > Address.
Select Create New to create the FortiGate address.
Enter a name for the address, for example FortiGate_network.
Enter the FortiGate IP address and subnet. <---- Is this mean fortigate Publice address and it's subnet?
Select OK.

Select Create New again to create the SonicWall address.
Enter the name for the address, for example SonicWall_network.
Enter the SonicWall IP address and subnet. <---- Is this mean sonicwall Publice address and it's subnet?
Select OK.
===

===
Configure the SonicWall Device
Create the address object for the FortiGate unit to identify the FortiGate unit's IP address for the VPN Security Association (SA).

To create an address entry

Go to Network > Address Objects.
Select Add and enter the following:

Name: FortiGate_network
Zone Assignment: VPN
Type: Network
Network: FortiGate IP address  <-- Is this mean the remote fortigate Public address and it's own netmask?
                                                   like 202.133.222.133/255.255.255.240 ?
Netmask: FortiGate netmask

Select OK.
===

===
Configure the VPN settings for the VPN tunnel connection.

To configure the VPN, go to VPN.
Ensure Enable VPN is selected in the VPN Global Settings section.
Select Add in the VPN Policies area.
Select the General tab and configure the following:
IPSec Keying Mode: IKE using Preshared Secret.
Name: FortiGate_network
IPSec primary Gateway Name or Address: IPSec gateway IP address <--what it's mean? my sonicwall public IP address ?
Shared Secret: Preshared
Local IKE ID: IP Address (address left empty)
Peer IKE ID: IP Address (address left empty)
===

thanks