I can't locate my fusion drive - sorry new here :(

I apologize in advance if there is already a thread for this issue. I purchased my brother's lightly used 2017 iMac which comes with a 1TB Fusion Drive. My brother reinstalled the OS to clean everything up and everything is working great.

The only issue is that I don't see the 1TB Fusion Drive. Under Storage I only see a 28 GB

Flash Storage, no fusion drive. Under the System Report here is what I'm seeing:

BSD Name: disk0

Partition Map Type: GPT (GUID Partition Table)

Removable Media: No

Volumes:

EFI:

Capacity: 314.6 MB (314,572,800 bytes)

BSD Name: disk0s1

Content: EFI

Volume UUID: E783267B-A4C3-3556-B751-DBED770EB996

Macintosh:

Capacity: 27.04 GB (27,035,381,760 bytes)

Available: 12.24 GB (12,242,223,104 bytes)

Writable: Yes

File System: Journaled HFS+

BSD Name: disk0s2

Mount Point: /

Content: Apple_HFS

Volume UUID: F0D959B6-426B-35E0-AD0F-30DC165F8B0A

Recovery HD:

Capacity: 650 MB (650,002,432 bytes)

File System: Journaled HFS+

BSD Name: disk0s3

Content: Apple_Boot

Volume UUID: B8119714-2DE9-30A7-B185-9975A971D4C3

I love macs, but I have no idea how to correct this issue. Could anyone assist me?

Mahalo - Keoni