Doubts regarding roles & participants creation

Hi All,

    I am  a newbee with bonita. I have downloaded the latest version(4.1.1). .

I am able to deploy the WebSale barfile using bonita console.

But i have few doubts about creating roles & participants.

How can we assign roles to the different participants. user can login thru the console & he can excecute any activities regardless of the participant.

Actually as per my requirement i have to use different users for excecuting different lind of activities

ie.

One user will login as Customer & he will raise the request.

Another user will login as agent & he will do the sales review.

Like this i have to Assign Roles for different console users.

Hope you understood my problem

Thanks In Advance

-Bins