To create a sales order using AL you need to create a Sales header and then sales lines. A simple code can be like this function below where you give customer No and Item No, and then document is created.
procedure CreateSalesHeader(CustNo: Code[20]; ItemNo: Code[20])
var
SalesHeader: Record "Sales Header";
SalesLines: Record "Sales Line";
begin
SalesHeader.init;
SalesHeader.Validate("Document Type", SalesHeader."Document Type"::Order);
SalesHeader.Validate("No.", 'SO100001'); //if Number from No. Series is required then comment this
SalesHeader.Validate("Sell-to Customer No.", CustNo);
SalesHeader.Insert(true);
SalesLines.Init;
SalesLines."Document Type" := SalesHeader."Document Type"::Order;
SalesLines."Document No." := SalesHeader."No.";
SalesLines."Line No." := 10000;
SalesLines.Type := SalesLines.Type::Item;
SalesLines.Validate("No.", ItemNo);
SalesLines.Validate(Quantity, 1);
SalesLines.Insert(true);
end;
