drum track

Hello ,can anyone tell me how to put a drum track on project and then adjust its tempo or beat to suit the already recorded project.
have recorded guitar and vocals and now want to add a simple drum track ,have found a suitable pattern from groove agent 5 ,exported it to the project however its slighlty out of sinc and requires some slight adjustment ,when I adjust it in the transport bar from 120 bpm it works fine but it changes the whole project, the guitar and vocals as well so not ideal ,surely ther must be a way of changing just the drum track on its own ,have tried everything and searched for answers but come up with no answers to what should be a simple task !! driving me mad