It is supposed that:
you installed the softphone on your computer,
you already have any information necessary for connection of the telephone (see section 11.1 Information you need for connection of any software telephone).
Tested on X-Lite 4.1
Run the application and wait for the telephone to display on your screen.
The SIP Accounts table is displayed. Configure the first tab, Account (see figure 11.1 Account properties dialog).
Check the Call option in Allow this account for.
Enter your telephone extension in the User ID entry.
In the Domain entry, specify IP address or DNS name for the computer where the PBX is running.
In the Password field, enter the password provided by your administrator.
In Display Name, insert your name.
Check the Register with domain and receive calls option and fill in Kerio Operator's IP address or DNS name in Address,