2 hard drives

My hard disk died and I had to replace it. That same day Apple closed for the virus. I was able to pick up my computer 3 days later, but I could not get anyone at my local store to help with this issue. I noticed these drives immediately after I downloaded my data from the cloud. So many things were mixed up after the download including the listing in the left panel under "Locations". There was "My iMac", "Untitled - Data (Internal Drive) 1000 GB", and 'Untitled (Startup Drive) 1000 GB". They are both now in "My iMac". When I expand "Untitled" I get my applications, library, system, and users. The other data drive I get nothing when I expand it. I'm afraid to trash the untitled-data for fear there is something hidden in it. My iMac is probably the OS file. When I try to run Clean My Mac the picture of these 2 hard drives show up for me to choose, and My iMac does not show up. I want to clean this up for my own sanity.

'My iMac' contained my OS. Now these other drives are there also. My biggest problem is getting rid of the other 2 drives without getting rid of something I need. I thought of removing them to Zip drives and see if my computer still runs OK. The one disk has 'untitled' 48.53 GB on it including my Startup volume. The other 'untitled - data' has 1.1 MB on it. I did uninstall Clean My Mac. All this happened when I downloaded from the Cloud. I probably need to go through everything program by program and just reorganize it. I was hoping to somehow avoid this tedious job.