access primary key

You really want an autonumber for the primary key.

 You will also need to create a second unique index on enough data to ensure that you don't enter someone twice.

 Where they are is just another fact (field or "attribute") about the company as is what they are.


  Extra information can be handled in a number of ways. We'd need to walk through that to determine how best to handle.

Jim.

Also, since this sounds like your first DB and your aksing about keys, it's would be worth while to spend an hour on this:

.HOW TO: Introduction to Application & Database Design using Microsoft Access
http://www.youtube.com/watch?v=4YH6gG0Y660

Jim.

Autonumber type is used for data that is not localized (i.e not known to the company). For example adding customers you need autonumber as primary key.

For company employees you can use predefined ids.
When using CustomerID in other tables as foreign key, it is a number and can be linked to the Customers table whose PK is autonumber.

You may start with a template from  available templates or Office.com.
Use Northwind database tohelp in designing your required database.

Jim,

Is there local help from expert exchange?, or can the communication can be via phone?

Northwind where can I find that?

No that one wont work.

From the topics listed, I assumed using Access database.

"Is there local help from expert exchange?, or can the communication can be via phone?"  
If you are really over your head and want somebody to help you personally, you can look up experts profile and if they have a listed address, you may contact  them probably on a for hire basis.  But first try here as there is really no question too difficult especially with databases and access.  

Instead of trying to do everything at once, take it in bits by asking separate questions.  The first thing to do is set up your tables.  And before doing that, make sure the data is normalized.  http://en.wikipedia.org/wiki/Database_normalization  

This should really be your first question, getting help on your data tables and possibly reformatting or breaking out your database.

I don't think there is enough information available to advice on your design issues.

e.g. take a well known global supplier like:
IBM

which has smaller entities - such as:
IBM USA
IBM Australia
IBM Europe

Is this one supplier (IBM) or 3? (3 legal entities, different currencies, different taxes etc.)

Will you need a hierarchy of suppliers? e.g. you have both IBM and the many legal entities that belong to IBM.

You can either use a GUID as autonumber key (select Autonumber/Replication ID when creating the field); or you can use a compound unique key made from one fixed key unique for each location and one traditional (Long) autonumber.

/gustav