A Mac doesn’t normally have what you call ‘multiple drives’. The hard disk, or the SSD, isn’t split into sections and instead is one whole storage area. Other external drives that you mount appear as separate drives. If you need to access your Mac drive often, you can add it to your desktop however, if you prefer a clean desktop but still need to access the hard drive, as well as other drives frequently, you can add Mac to the Dock. This is much like adding My Computer or This PC to the taskbar on Windows.
Add Mac to Dock
Open Finder and navigate to the following location;
Inside the CoreServices folder, look for the Finder app. Right-click it and select Show Package Contents from the context menu.
In the Folder that opens, go to;
Here, you will find ‘apps’ that you can access from Finder such as AirDrop and iCloud Drive. You will also find ‘Computer’ here which is essentially the root of all mounted drives on macOS.
Drag & drop Computer from this folder on to the Dock.
When you click it, a Finder window will open Your Mac/MacBook where you can view all connected disks, Network, and Remote Disc. If you’ve mounted other drives, they will also appear here.
This is just a quick way to access Your Mac. The drives can be accessed from the desktop if you’ve enabled them to appear there. Additionally, you can access Your Mac from the sidebar in Finder where, in addition to other folders, you will also see all mounted drives.
Adding Mac to the Dock isn’t going to create a new location on your system. This is simply a quick, and alternate way to access your drives and the network all in one place.
To remove your Mac from the Dock, i.e., remove Computer from it, right-click it and from the context menu select Options>Remove from Dock.
One major difference between Computer on macOS and This PC on Windows is that you can add any folder and file to Computer. You cannot do the same for This PC. You can add network folders but not other folders or files from your PC.
To add folders and files to Computer on macOS, all you have to do is drag & drop the item on to it. You will have to authorize the change with the admin user since this isn’t an edit/change you should make lightly but beyond that, it’s a simple process.