It depends on several factors. Being a P2P exchange, the main variable is the taking of your offer by another person. Your post will be available for up to 23 hours and will then be automatically deleted if it is not taken.
Once an offer is accepted, a 15-minute window is opened to pay the lighting bill and for the bot to contact both parties. From here, they have a maximum time of two hours to complete the operation. After those two hours, the order expires and the sats will be returned to the wallet they came from. For this reason users must only use instant fiat money payment methods.
As both participants are online and agree on immediate payment methods, transactions are almost instantaneous.