Confused with in-game help on running multiple clients

Just as the title says, I need help running more than one Second Life client from the same computer. I read the in-game help, but I didn't understand it too well. Could someone please explain it to be better? Thanks.

create another SL shortcuit,
right click , properties on it,

go to shortcuit , then add -multiple , where target is

Target : "C:\Program Files\SecondLife\SecondLife.exe" -multiple

For some random reason sometimes SL goes kookoo when you have a SL up and start another and goes aaaweeefully slow on one SL

Wierd fix, minimize one SL, start other, wait till its logged in, then you can use other, and have zero lag, hope you have a dual core : P