Connection.php connects database
Signup.php inserts value in the database
login.php uses function to check if value entered is correct or not
functions.php Contains the function which helps in login
index2.php We are sent to this page after we log in. Here we can upload file.
upload folder is where we upload the files given by the user.
turn on xampp, run apache and mysql save these files in htdocs folder(all files in the same folder of htdocs) go to phpmyadmin and create database and create table. then go to localhost and go to ur folder and it will run.