One of the best resources on the web is Chabad.org.
It is packed with information, classes and anything you wanted to know about Pesach.
The Union of Orthodox Rabbis has a very informative list on what needs Rabbinic passover supervision and what is fine with the standard rabbinical symbol.
It also has very clear instructions on how to kosher the kitchen.
View the The OU guide to Passover 2024.
