As was already said, you just replace the red information. Here's an example.
on *:text:*:[color:red]#channel1[/color]:{
if ($network != [color:red]Efnet[/color]) return
if ($nick == [color:red]oshru[/color]) && ($network == [color:red]Efnet[/color]) {
scid -at1 if ($network == [color:red]Dalnet[/color]) msg [color:red]#channel2[/color] $1-
}
}
Note that I also added a check so it will copy text only from #channel1 on network1 rather than any channel on network1, or from #channel1 on any channel.
Now, the only thing you'd replace the channels (assuming you want it from your nick and you want those particular networks... otherwise, replace all the reds).
As it is currently written, it will relay all messages from your nick in Efnet #channel1 to Dalnet #channel2. If the networks are reversed of what you want, just change them. If you don't want it from your nick, change the nick.
Just change anything red to whatever you need.