Task Specifc SD Transaction Codes 1

How to configure tax?
Use the following Tcodes:
OBQ1 --- CONDITION TABLE 
OBQ2 --- ACCESS
OBQ3 --- TAX PROCEDURE CAL 
OBBG --- ASSIGN COUNTRY TO TAX PROC
OVK3 --- CUSTOMER TAX CATEGORY 
OVK4 --- MATERIAL TAX CATEGORY 
OVK1 --- TAX DETERMINATION RULES 
OVK6 --- ASSIGN DELIVERY PLANTS
and thenVK11 to maintain the condition record for the tax rate. 
I raise a sales order and is getting a error stating that "sales area is not defined".
1) At SPRO-->SD-->Sales header-->Assign Sales area to Sales document - Combine your Sales Organisations, Distribution Channels & Divisons
2) At VOPA-->Assign Partner Determination procedure to your Account Group of Customer Master you are using.
3) At VOPA--> Assign Partner Functions to your Account Group & Partner Determination procedure
Steps to create a Vendor Master Data at the client level and how do we extend it to different company codes?
Follow the following steps:
  1. Create a vendor account group   OBD3
  2. Define no. range for vendor account group    XKN1
  3. Assign number range to Vendor account group   OBAS
  4. Define tolerance Group for vendor     OBA3
  5. Create 2 GL accounts    FS00
          a) Purchases A/c
          b) S. creditors A/c
  6. Create Vendor master data     XK01
  7. change/block vendor master data   XK02/XK05
  8. Define document type and no. range     OBA7
        a) KA
        b) KG
        c) KR
        d) KZ     
How to find the strategy group in sap sd?
Menu path for Strategy Group is:
Spro --> Production --> Production Planning --> Demand Management --> Planned Independent Requirements --> Planning Strategy --> Define Strategy Group.
OPPT -- Maintain Starategy Group
We can see Strategy Group in Material Master Record - MRP 3 - Planning -- Strategy Group.
  10 - For Make to Order
  20 - For Make to Stock