How to create Search Box ?

You need to try first. Follow these steps:
1. Design a page where you place few search parameters. For example, searching a name in DB, so a textbox for it.
2. Now, place a search button as the trigger event of the search. On click of search button you would be writing your logic.
3. In search button click, get the search parameters (like the name in textbox here), use it, form a query and execute on database
4. Get the query result back in a datatable and bind it to a grid or any other appropriate control based on your needs
5. For now, Datagrid will display the retrieved result.

Done!