To completely configure the SME server you will need to use both the Admin panel and the Web Based Server Manager.
The Text Mode you should only need to do once, this is where you will set your Domain Name, System Name , Mode the server will run in (gateway, Server, or Server/gateway), Internal IP address and the mode for connecting to you ISP if your using as a Gateway. This should have been done as part of the inital setup.
Once your system is on line, then everyday tasks such as adding users , Ibay, etc is done from the Server-Manager web page.
THT,
Darin