APEX

I'm a Newbe in Oracle .. sorry..
I have read the OLE_DB example... hmmm its for an older version only so it doesn't work with 10g But even there is no DATABASENAME in the example then 'exampledb'
So how to build the connectionstring. Its so pretty easy in MS Access what I did the last 15 years. I cannot find out. I never have given this database a name during installation. I'm not intersted in connection by HTML because I have existing VB programs to adapt from MS access to Oracle In MSAccess we had different databases where each has its own name. Here I have creates a User and under this user now I can create tables. OK But when connecting to the database: whats the databasename itself. ?? Which path has to be set.
My Oracle 10g is installed on c:\oraclexe\... Whats the database file. In Access easy : its the .mdb file and here.
The helpsystem is a very big one here.. But VB 6.0 examples seems to be deleted, respectively its not tell anywhere to create a databasename. Its impossible to read thosends of pages in English for a German user. Its obviously a total other system to use.
And when finished with connection on the server how to connect via LAN to this database. I'm really a bit hopeless in the moment. Anybody here who can explain me how to do ?

Do I have to do some specific actions when I have finished the 10g setup, before I can access with ADO ?
There is an example in it where user is 'hr' password = 'hr' so please tell me how to access this with a normal conectionstring in ADO technique.
Thx in before