Searching for Chameitz
One must search all their property on the night before Pesach. This includes one’s car and any office space which is owned or rented. If it is very inconvenient to check one’s office on the night before Pesach then one should search for chameitz in their office on the night before.
If one will not be home for Pesach then one should check their home for chameitz the night before they leave.
If one will be staying at someone else’s home for Pesach it is not the guests obligation to check. However, if one is renting the room (like at a hotel), they must check the room for chameitz. If they arrive at the hotel on the eve of Pesach, they must check for chameitz upon arrival.
One only says the blessing of bedikas chameitz if they are searching for chameitz the night before Pesach. Otherwise, the search is done without a blessing.
One makes a blessing before searching: Baruch… asher kid’shanu b’mitzvosov v’tzivanu al biur chameitz (Blessed are….Who sanctified us with His mitzvos and commanded us to destroy chameitz).
Since one’s home has been cleaned thoroughly for Pesach at this time there is a concern that the blessing be made is being said in vain. For this reason, there is a custom to hide ten pieces of bread before the search so that there is definitely some chameitz that must be found. That being said, the purpose of searching is obviously not just to find those pieces. One must search for any chameitz that they may have missed.
Although some search with a candle as this was done throughout history, it is totally acceptable and, if it is more efficient, even preferable to use a flashlight. One may leave their lights on if this facilitates the search.