First, navigate to the URL of the Synology you've been provided.
Login with the username and password you've been provided.
From the top right, select the four square icon and then select the desired backup you'd like to access (for example, mail)
Using the icons at the bottom left, you can view the mailbox/backup as it was on that particular date. This is helpful if you're trying to find an item from the backup that was later deleted. You can also use the arrows to jump back to each backup day by day.
