Sales Organisation is the organisational unit which responsible for the selling of the product, movement of goods to the customet,customer right of recourse

Sales Area is the combination of the Sales:
Organisation + Distribution Channel +  Division.

Company code of an organisation is the legal entity which have separate Balansheet and profit & loss A/C required by law for the legal purpose so whenever an organisational unit have different Balance sheet and P/L A/c you can define a company
code.

Organistational Structure broadly refers to the way a company follows a set path of systems/hierarchies.
Different companies do have different structures and the differences in structures emanates basically from the strategies. STRUCTURE FOLLOWS STRATEGY...

A Company's structure can be mapped in R/3 which would facilitate flow of information, flow of process and also facilitates work flow in a logical way.

A Sales Organisations structure is based on the Elements of the Organisation which are as follows.

1. Comapny Code
2. Sales Organisation
3. Distribution Channel
4. Division
5. Plant
6. Shipping POint.

A Company Code is generally created by finance guys and it broadly represents the highest point of structure.

The relation between Sales Org and Company code is Unique. One Sales Organisation can be assigned to one Comapny code.

A Combination of Sales Org, Distribution Channel and Division is called a Sales Area and a Sales Area is assigned to the company thru the Sales Orgn.

A plant is assigned to the company code. It is also assigned to the Sales Org and Dist Channe and this channel is called Delivering Plant.

A Shipping POint is assigned to the CLIENT.