Provided are a method for a first device to perform wireless communication, and a device for supporting same. The method may include: receiving, from a second device, a first sidelink control information (SCI) through a physical sidelink control channel (PSCCH); receiving, from the second device, a second SCI through a physical sidelink shared channel (PSSCH) related to the PSCCH; determining a physical sidelink feedback channel (PSFCH) resource, based on an index of a slot and an index of a subchannel related to the PSSCH; and determining whether or not to transmit hybrid automatic repeat request (HARQ) feedback information for the PSSCH to the second device on the PSFCH resource, wherein a format of the second SCI is a first format which does not include location information of the second device or a second format which includes location information of the second device.