where do I file my major purchase?

This might be an old note but should get you close.

Enter Sales Tax under
Federal Taxes or (Personal for Home & Business)
Deductions and Credits
Then scroll down to Estimates and Other Taxes Paid
Sales Tax- click the Start or Update button

You might see a screen saying
Sales Tax and Income Tax - Click Continue with Sales Tax
Then click on EasyGuide

Enter your State and Dates you lived there
Enter your Sales Tax Rate as a whole number like enter 7% as 7.00 or 7.5% as 7.50
Then enter any major purchases

You may be able to get a tax deduction for the sales tax paid on your major purchase. You will see that in the Deductions and Credits section, then Estimates and Other Taxes Paid, then Sales Tax. However, you will only benefit from deducting sales taxes if they are more than your state income taxes, as you can't deduct both. Also, you need to be able to benefit from itemizing your deductions for the sales tax deduction to benefit you.