You may need your ACAS Early Conciliation certificate number, employment contract, payslips, dismissal or disciplinary letters, grievance records, relevant emails or messages, and a clear timeline of events. If claiming money, include evidence of your losses and details of any benefits or earnings received after the dispute. The tribunal will usually set directions explaining when to exchange documents, prepare witness statements and provide a schedule of loss, so keep originals and organised copies. The exact evidence depends on your claim, and a solicitor regulated by the SRA or a recognised advice service can help you prepare it.