The admin tool is called pgAdmin III and is found from the Start menu.
It looks and works pretty much like most admin tools (Eneterprise manager, SQL Server studio, Sqlyog etc) so if you are familiar with those I guess you will be able to get started asap.
To create a database we just rightclick in the tree and select New database:
I wasn't sure here but I guessed some privileges was needed to define, so I gave publis full permissions (available on the Privileges tab).
To create tables
This is also pretty much like any admin tool.
However please note that contraints(primary keys etc) are defined only on the special Contraints tab.
As for datatypes, please look at this article on Postgresql datatypes
Query tool
The admin tools also offers a pretty decent query tool
and a data editor
