What are the classes, Tables, Forms and Methods used to post the sales orders in AX

SalesTableType and SaleslineType classes will get called while creating the orders.

SalesFormLetter* classes will be used to post the sales order at various document

status(packing, invoice etc).

SalesParm* tables are used to prepare the data for posting 

CustConfirmJour, CustConfirmTrans - when a sales order gets confirmed

CustPackingSlipJour, CustPackingSlipTrans - when a packing slip is posted.

CustInvoiceTable,CustInvoiceTrans - when an invoice is posted.

These are some of the mainly used tables.