Hello I am looking to use transistions from one page to another. How do I go about doing it?

Thanksss

You can't really make transitions between two pages, but you can give a better impression with something like this.

// Hide your main div when leaving the page
window.onbeforeunload = function() {
    $("#myMainDiv").hide('fade');
};

// Shows your man div when loading the page
window.onload = function() {
    $("#myMainDiv").show('slide');
};

Is this javascript? DO i use this in CSS?

it is javascript,
it will not work all the time, (IE<9 of course, or high security settings), when it does work (justabout everything else) it is effective.
it may add to apparent page load time,

onload and onunload scripts, are often considered malware, as the popup porn industry, and may get, if used injudiciously, any external code, penalised delisting from ser,

NOT displaying the most important part of the page immediately, kills user retention, the user wants the content NOW thats what they came for, display everything else whenever you like