Update for Comment I am successful in sorting out the prob of user recognition for the few pages that I have set up for the users once logged in.
You are definitely going to need a database to hold information for each of your users. Start looking into MySQL server and once you have one setup, follow some tutorials for php mysqli and php form. The below is extremely rough but it should give you an idea of how to attack your problem. Good Luck!
index.html
<form action="addSkills.php" method="post">
<input type="text" name="skill"/>
<input type="submit">
</form>
addSkills.php
$skill = $_POST['skill'];
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
$result = $mysqli->query("INSERT INTO user (skill) VALUES('$skill') WHERE userId = $_COOKIE['userId']")
$result->close();
$mysqli->close();
This is a huge undertaking, you should try separating this into tasks and try working on each task at a time. One place to start would be able to navigate from page a to page b and still being recognized as logged in, once you do that look into forms and submitting forms.