Hi Debi! I did a quick search for a visual timeline that might help you to see Cyrus as a contemporary to Nebuchadnezzar. You can fact check and do more research to confirm this, but this timeline seems to be a pretty good breakdown: https://totallyhistory.com/daniel-timeline/
Otherwise, you can see Cyrus in the book of Daniel as Nebuchadnezzar’s successor in Daniel 1:21. (Daniel served Nebuchadnezzar king of Babylon (Daniel 1:1) until the first year of King Cyrus (Daniel 1:21)).
Does that help?