We will divide the post into 2 part. One for purchasers and another one for sellers.
By the closing day, the purchasers lawyer would have received the keys from the seller's lawyer's office and funds from the bank would have been requested. The purchasers would have already brought their portion of funds to the lawyer.
Once the funds are received from the lender, the purchasers lawyer will get the funds to the seller's lawyer's office (A certified chq delivered by courier or direct deposit to their trust account). Once they receive the funds and related paperwork, they will electronically sign the transfer deed for release and the purchaser's lawyer will register the transfer deed and mortgage.
Once that is done, the property is registered under the purchaser's name and the keys can be released to the purchaser's. A most commonly asked questions is "When do I get the keys, what time?". Depending on when the funds were received from the bank and then transferred to the sellers lawyer, then release of deed etc, the process could be done by 1 pm or 5 pm (That's when the land registry closes) so most lawyers would not promise the delivery of keys to the purchaser's before 5 pm. If the registration process is complete by 1 pm, then the keys can be given at that time but there are many variables and number of actors involved, so for planning purposes (Moving, Appliances delivery, Prayers etc) key delivery should be factored in after 5 pm.
The funds are received from the purchaser's lawyer and by the closing day, at least a set of keys has already been delivered to the purchasers lawyer to be held in Escrow until the transfer has been registered. Once the funds are received, the sellers lawyer will will electronically sign the transfer deed for release and the purchaser's lawyer will register the transfer deed and mortgage. After that the funds received from the purchaser's can be used. First and foremost is to pay the existing mortgagee (Deliver a chq to the bank as per payout statement) or mail the chq.. Then real estate commission is paid (Chq is normally mailed to the office) and then the balance of the funds can be given to the sellers (Mostly on the same day or next day). They can also be direct deposited if a void chq is provided and it's one of the big banks in the area.