The users to be simulated are defined in the workload section of the test script. A virtual user is denoted by the transactions to be called, along with their frequency.
Usually, user behavior implementation is divided into at least three separate parts: initialization, user actions, and shutdown. Note the user group definition in the BDL sample below:
dcluser
  user
    JavaUser
  transactions
    TInit         : begin;
    TMyJavaTrans  : 1;
    TEnd          : end; 
            	 Here is a BDL sample that includes multiple transactions:
dcluser
  user
    JavaUser
  transactions
    TInit           : begin;
    TMyTransaction1 : 5;
    TMyTransaction2 : 2;
    TMyTransaction3 : 8;
    TEnd            : end;