Before you do anything regarding cross-save, you need to migrate your Battle.net data to Steam. Yes, that is a one time only thing, so make sure that you have the correct Battle.net account linked, and the correct Steam account. Once that data transfer has been initiated, it is permanent. This is done on the PC Move page. Once you’ve migrated that data to Steam, then you can look at setting up cross-save between your Steam and PSN accounts. Again, make sure that you have the correct accounts linked before proceeding. When setting up cross-save, you will be asked which set of save data you wish to make primary or active. You are to choose the set of characters you want to play across both linked platforms, and the other set of characters will become dormant. Make sure you choose the correct active account. If you have not already done so, read the FAQ on the main cross-save page, and ask any questions before activating the feature. If you need to deactivate for any reason, there is a 90 day cooldown period, so it’s best to fully understand how everything works beforehand.