The signing of the preliminary contract binds the parties, (yourself, the developer or builder).
This being said, the Civil Code of Quebec provides that you have the right within a period of 10 days to unilaterally cancel this contract, which means that you can walk away from your undertaking to purchase (right of withdrawal) without any justification. This "right of withdrawal" may be exercised by any promisor who is a natural person and who intends to occupy the apartment being the object of the preliminary contract.
The developer needs to make a large investment to build an immovable in co-ownership. Therefore, he will require a deposit at the signing of the preliminary contract. The deposit is your first payment to the vendor. The amount should be proportional to the purchase price of the apartment.