Harq feedback timeline protocol

Hello experts
The timeline between the reception of data, harq acknowledged feedback from UE and nack delay and SR confuses me. Can someone please explain to me what the flow looks like? Here is my thinking…
Gnb sends pdsch if it’s harq 16 then it transmits 16 times then it wait for the ack or nack? The UE sends harq feedback on pucch but pucch requires SR?