Where is it not available? You can't apply the purchase to the Online version. We see people all the time that bought the Desktop program but somehow ended up in the Online version. If that happened to you we can tell you how to switch to the Desktop program you bought without needing to start over.
You need to download and install the program you paid for. To access your download, sign in to your TurboTax Advantage account and look for My Downloads.
https://turbotax.intuit.com/personal-taxes/cd-download/advantage
How to install the Desktop program
https://ttlc.intuit.com/turbotax-support/en-us/help-article/product-delivery/download-software-turbotax-com/L7u9oLEkq_US_en_US?uid=luqgvzrd
How to Activate the Desktop program
https://ttlc.intuit.com/turbotax-support/en-us/help-article/license-information/install-turbotax-cd-download-software-license-code/L1wFOSXur_US_en_US?uid=lnz7f146