Building a shareholder database using access 2007

I am trying to build a database for shareholders and the companies they are
shareholders to. It has been quite a while since I build my last database and
2007 is very different to what I last used. I undersand I need enough tables
so I don't repeat entries and also that I need to relate the tables to be
able to build queries or forms. However, as I have many to many relationships
as well as one to many I am confused as to where to use queries and even if I
need to.

I have two tables on the company side and about five on the shareholder
side. Ideally I would like one form to enter information for the shareholder
and another for the company but it looks like that may not be possible.

I am book for a training course in Access 2008 but it is two months away and
I am being pushed to deliver the database asap.
Any suggestions or help would be greatly appreciated.