Hi I'm not a CPA/expert and others can weigh in, but this article should help on the steps:
https://ttlc.intuit.com/turbotax-support/en-us/help-article/retirement-benefits/enter-backdoor-roth-...
As described there are generally 2 parts to this (based on desktop version):
1) Under Deductions&Credits / Retirement and Investments, you would put in the details of the IRA contribution which is presumably (and necessarily) nondeductible. This should generate form 8606 (see under Forms view) which will track the basis and do the key calculation for the tax on the conversion.
2) You'll get a 1099-R for the $8004.63 from Vanguard to input under Wages&Income / Retirement Plans with the appropriate coding in Box 7 (code 2).
If this is your only IRA and that MV at year-end was $0 after the conversion, then Form 8606 should end up determining you did an 8004.63 conversion on a cost basis of 8000 and the 4.63 is taxable, and feed that into Form 1040 line 4.
Hope that helps.
