Parameterization for loadUI

Hi,

I am trying out this tool and would like to understand what is required in order to add parameters to a load scenario.
Iam currently trying out a simple login scenario with 2 parameters - login-id and password.

From my current understanding we need soapUI also in order to do this. Is that right?
An outline of the methodology would be great to have.
Also is there a pdf or help file with loadUI?

Regards
Vinod