Sales organization is an organizational unit that sells, distributes products, negotiates terms of sales and is responsible for all the transactions involved with a sale.

Migrating from the existing system on which currently working to the SAP system is called the legacy system. Cutover strategy that depends upon how the organizations design their data load strategies. Normally, it decide the sequence of Data loads for Configuration  settings, Master data, Transaction data which follows whom and then it make a copy of the system as a  Production system a day before and after checking the successful data loads, you go-live 100% or partial again  depending upon organizational setup and policies. Cutover planning is highly site specific. There's no thumb rule. The stock data as on the date of going live should be correctly entered. But stock being a highly dynamic quantity, the strategy for loading should be crystal clear. Then you have to load all the back dated transaction on the stock. Some stock comes into your plant/storage location as return and some stock is actually delivered to your customer through sales orders of various kinds. 

The transaction code for creating a material in SAP is MM41. MM01 is the transaction code to extend a material.

When a value is not entered for a manual and mandatory condition type the pricing procedure will reject the conditions in the sales order. There would be no header condition type to have an access sequence.

The examples of Global Settings are Currencies, Countries etc and this data is application independent.

A general customer that is created for those customers for which it do not want to create separate records is called a one time customer. This customer can be reused.

According to customer master record a Payer is the individual or company who will settle the invoices for products or services sold.

Normally account groups are defined by the finance team and some of the tables in SAP SD for customer master are KNVV, RF02D, KNA 1 etc.