Please see below screenshots with configuration settings.
Notice: use your own extension number (4 digits) and your own password
IMPORTANT: sip port number in the pictures below may be different for your account.
e.g. for JUPITER PBX its 5067 (sip.voipline.net.au:5067) This goes into the domain section
Click on softphone then account settings
Then fill in account details similar to below using your extension number and password