For doing parameterization,first select the variable which you want to parameterize,right click on it and select 'replace with parameter' enter parameter name, click properties button,enter name in the Path field,click 'create table' button,select 'By name' radio button,enter the name of the parameter.in 'select next row' rowfield,if you are doing parameterization for UserId means you can enter Unique,in 'update value on' field enter Once.based on the application you can select that two fields(select next row,update value on).then close the window,click OK in next window.So,that variable will parameterized.