JDBC

i have a real big problem understanding JDBC, here is the situation, i have a database in Microsoft
Access which consists of 3 tables with the following details:
*Student Details: ID, Name, Address, Course, Year of Study
*Course Details: Name of Course, Total number of students, units taught
*Staff Table: Name, Room, email, Units Delivered

(i have used ODBC)

Q1 - how do i extract information from the database in JAVA Applet
Q2 - how do produce a username and password to get access to the database
Q3 -  how do create queries

CAN U PLEASE HELP ME WITH THIS PROBLEM!
I WILL BE MOST GREATFUL IF U CAN SEND ME EXAMPLES AND STEP BY STEP HELP ON HOW TO PERFORM THE ABOVE
QUESTIONS

THANKS