I'm preparing the sequence diagram for a project. I started with the sign up operation.
It's confusing to me because this is the first time I use this technique with a real project.
The following image is part of the registration process, would any one take a look and correct me if I did any mistake.
This looks good. I would suggest avoiding use of alt and doing only one scenario per sequence diagram. Label the sequence diagram with a note containing summary, precondition (what has run before), and postcondition (the state after the scenario has run).