Select "URL prefix," enter your domain name, and click on Continue.
Go to the "HTML tag" tab and copy the meta tag.
On Tilda, go to the Site Settings → More → Ownership verification. Paste the meta tag in the "Google domain verification by meta tag" field. Publish the website.
Don't paste the whole line. Only the content part in between the quotation marks is required: <meta name="google-site-verification" content="SgMh4j7HC44PATndqFrUWk-j4NqSnPn_wEPXJuZZRMg" /> The required part is highlighted.
Go back to Google Search Console and click on Verify.
Your website ownership has been verified.
Alternative method: add a TXT record to a domain registrar