Concurrent edition of a record

I am trying to understand how the LockType parameters work in the practical world, but I am having difficulties to find a sample code that really illustrates their effects.

I want to generate a code in which if a second user tries to open a recordset to edition, he will get a message that the record is being edited by another user.

In the first page the user is presented with a list of the records.
He can only view the list, but at the end of each line he has buttons to EDIT or DELETE each specific record on each line.

If the user clicks on an EDIT button of a certain line (record), he will be taken to another page, where there will be a form where he can change the information of that record.

To present the data in that form I used
"rsTable.Open sqlSearch, SqlData, adOpenDynamic, adLockPessimistic"
with the hope that while he has that page open in his computer, other users would get an error message if trying to open that same record.

I have two computers at home.
I made the test and it didn't work.

Can anybody give me a clue?