Arbitration proceedings are governed by the so-called lex arbitri. This law regulates the actual arbitration proceedings themselves, not the substantive matters under discussion. It is therefore necessary to distinguish between substantive issues and procedural issues. The former are those which underpin the decision on the case and the reasoning behind it; while the latter refer to the process by which that decision is achieved. The parties are free to agree on the procedure to be followed by the arbitral tribunal in conducting the proceedings. Failing such agreement, the arbitral tribunal may conduct the arbitration in such manner as it considers appropriate.