Installing OneDrive for Biz

As has been said, you just sign in with the appropriate account, if it's a work (or school) account it will be recognized automatically as a OneDrive for Business, otherwise with a Microsoft account, it will be OneDrive - personal.   

This is done from the same place, from the OneDrive program built-in to Windows 10 and available for https://support.office.com/en-gb/article/onedrive-desktop-app-for-windows-850703dd-ea56-4c7a-bff5-6c2e4da227cf, for example, or the mobile apps etc.

Here is what it looks like from Windows 10

Both OneDrive for Business and OneDrive personal were added from the above option in this example:

You also get the two system tray cloud icons, a blue one for OneDrive for Business and a White one for OneDrive personal.  Both of these were added from the same default OneDrive program.

These articles will be of interest if you are after more information -

https://support.office.com/en-us/article/What-is-OneDrive-for-Business-187f90af-056f-47c0-9656-cc0ddca7fdc2

https://support.office.com/en-us/article/sync-files-with-the-onedrive-sync-client-in-windows-615391c4-2bd3-4aae-a42a-858262e42a49

https://support.office.com/en-us/article/sync-files-with-the-onedrive-sync-client-on-mac-os-x-d11b9f29-00bb-4172-be39-997da46f913f