Sorry you need a full Windows or Mac computer to install the Desktop program, not an iPad or mobile device. The iPad can only use the Online browser version. There is a Mobile App which is just a portal to the Online version.
You can't apply the Desktop CD/Download purchase to Online. You have to pay for Online separately. You will have to get a refund for the Desktop program. Then you can use the Online web version. Or try to upgrade your Computer or find another computer to install it on.
Try to get a refund from Staples. You can try to get a refund from Turbo Tax, submit an online refund request within 60 days of receipt here https://ttlc.intuit.com/turbotax-support/en-us/help-article/intuit-refunds/request-refund-turbotax-p...
