International trade letter of credit

I am a business man of import and export and want to know about the international Trade letter of credit details, what are the norms of the letter of credit and what will be the mode of payment in this and what is the agreement and rules for the international trade letter of credit and what is the process and where should I do contact for this?

Trade letter of Credit is a letter from a bank which is guaranteeing that buyer's payment to a seller will be received on time and for the correct amount. If buyer is unable to make payment on the purchase, bank may cover the full or remaining amount of the purchase. Rules of letters of credit which made by the International Chamber of Commerce for make some significant changes that revision of Uniform Customs and Practices for Documentary Credits.