There are two ways to create a new workspace from the homepage.
At the bottom of the Workspaces sidebar, there's a + Add a workspace option. Click this to create a new workspace.
Alternatively, you can scroll all the way down to the bottom of the homepage to find another, larger + Add a workspace button.
Once you create a new workspace, you'll be prompted to give it a new name. If you create a new workspace, by default, you are the sole owner of that workspace.
Once you've created a workspace, you can invite some workspace collaborators and start adding bases to it.