We're pleased to have you here with us on the Ranch, but there are a few rules that need to be followed, and one is that proper names are required. Please take a look at the JavaRanch Naming Policy and adjust your display name to match it.
In particular, your display name must be a first and a last name separated by a space character, and must not be obviously fictitious.
I don't know who "u" is, but I'll try to give you a start:
1) When the button is clicked, a request is made to a servlet (usually via a form submission). 2) The servlet gathers the data for the entity to be added. 3) The servlet calls a "model" class that's in charge of persistance for the entity in question. 4) The model class uses JDBC to insert a record into the appropriate table. 5) Control returns to the servlet which forwards to a JSP that shows whatever results are appropriate.