tax loss harvesting question

Hi – I only have 1 taxable account and have only bought VTI in the past 30 days. I don't plan on having any gains to offset, but would like to tax loss harvest to offset $3,000 in ordinary income. Do I just sell all my VTI from the past 30 days (plus enough to get me to the $3,000 loss) and then buy something like ITOT? And then don't buy VTI or anything “substantially similar” for 30 days? Then I can deduct the $3,000 loss from my ordinary income? Am I missing something? Thanks!