Hi Marlon.
You've probably done the hardest part, which is getting the stuff in there in the first place (in my first project that's where i struggled the most!)
I'd say your next step is to display and edit it. The basic principle is the same - you're still submitting information for inclusion in a database.
What you have to do is populate the blank input fields from your add.php with information from the database.
Rather than doing a search, make a display of items first (it only need be 10) and learn how to display those key fields as a link - that link needs to pass the id for that row into the update page eg <a href="update.php?id=1">
In php/sql, make sure you tell sql to bring down the id for each entry, then give it a value. This will make your code look more like <a href="update.php?id=<?php echo $row['id']?>">
When you click that it will tell the update page (as long as you $_GET ['id']) that it needs to SELECT * from DB where id=$id
Then it can populate your fields with the correct information eg:
<input type="text" size="11" value="<?php echo $row['tel_no']?>">
Now that the fields have values you can tweak and edit them to your heart's delight.
The only thing that changes now is the SQL to UPDATE the code rather than INSERT it
For adding I imagine you used something like INSERT INTO db (field1, field 2) VALUES ($value1, $value2) - to update it's similar, but more like
UPDATE db SET field1='$value1', field2='$value2' WHERE id=$id.
As long as you can pass that id from one page to the next (and securely), you shouldn't have too many non syntax problems.
If you want any further help, drop us a line.