extremely newbie questions

I'm very new when it comes to databases, and I'd like to try out
pgAdmin on my Windows NT to create, configure and manage some
databases on a remote linux server.

I'm using pgAdmin 7.05 and PostgreSQL ODBC driver v6.50.00.00.
I've installed the above two as well as MDAC v2.6
And i'm running Windows NT Workstation with Service Pack v6a

1) I want to test out PostgreSQL on a windows platform, so is there
anything else I have to install other than the software
I have mentioned above? I assume that pgAdmin is something like
MSSQL server, or am I wrong? is it just a frontend?
2) where can I find a sample database which can be used for pgAdmin?
Can any regular database created by Microsoft Access be used?
(*.mdb)
3) i've tried creating a PostgreSQL ODBC connection with a Microsoft
Access database, but when I start pgAdmin and connect to the
source i've specified, this error message appears:

Error Details
*************
Error Number: -2147467259
Error Description: Could not connect to the server;
Could not connect to remote socket.
Error Source: Microsoft OLE DB Provider for ODBC Drivers
Subroutine of Function: frmODBCLogon, cmdOK_Click

Any help would be very much appreciated.
I can't even seem to open the main pgAdmin program!
And thanks in advance.

Warmest regards,
Nicholas Chan