Thank you for your inquiry. Skype for Business is not available as a standalone product. Instead, it requires an Office 365 Business subscription for any of the professional call service’s features to work. If you do not already have an account, you can go to the product website to get started. After that, you can sign into the service and download the app on your device. For more information about using Skype for Business, check out our article How to Use Skype for Business. If you need further assistance, you can contact the Skype Sales Team, by clicking here
Hi there! Skype for Business is pretty easy to set up, and Microsoft offers a very nice step-by-step walkthrough from download to setup at this page: https://support.office.com/en-us/article/download-and-install-skype-for-business-on-windows-2da94a13-6d16-4d67-adf3-439f2b946994?ui=en-US&rs=en-US&ad=US
Hope this helps!