[ydl-gen] How to setup an ethernet connection from the start?

[butters]

Am running YellowDog 4.0 on a Pismo 500 and would like to know how to 
just get up and running with an ethernet connection, the settings etc. I 
ruined my original and just would like to get it running again. I have 
some settings that I delete but every time I go to set it up again they 
reappear? Please any help would be appreciated.
K~