Based on an embodiment of the present disclosure, a first device configured to perform wireless communication may be provided. For example, the first device may comprise: one or more memories storing instructions; one or more transceivers; and one or more processors connected to the one or more memories and the one or more transceivers. For example, the one or more processors may execute the instructions to: receive, from a base station, information related to a physical uplink control channel (PUCCH) resource for reporting hybrid automatic repeat request (HARQ) feedback information and information related to a configured grant (CG) resource for sidelink (SL); generate ACK information, based on no physical sidelink control channel (PSCCH) transmission by the first device on the CG resource in a single period; and determine a priority value of the ACK information. For example, the priority value of the ACK information may be same as a largest priority value among at least one possible priority value related to the CG resource.